Obesity: Assessment and the evaluation of obesity prevention and management programs

Group of experts and authors

Arnaud basdevant, Nutrition, University Pierre and Marie Curie, UPMC, and Hôpital Hôtel-Dieu, Paris

Françoise bas-theron, General Inspectorate of Social Affairs, Paris

Pierre combris, Research laboratory on consumption, inra-corela, Ivry-sur-Seine

Pierre ducimetiere, Unit 258, Inserm-University Paris Sud Hôpital Paul Brousse, Villejuif

Marie-Laure frelut, Pediatric therapeutic center, Croix Rouge Française, Margency

Martine laville, Service of endocrinology diabetology nutrition, Hospital Edouard Herriot, Inserm U 870, Research center on human nutrition, Rhône Alpes, Lyon

Ambroise martin, Faculty of Medicine Grange Blanche, Lyon

Chantal simon, Nutrition, EA 1801, University Louis Pasteur et service of internal medicine and nutrition, Hospital of Hautepierre, Strasbourg

Maïté tauber, Medico-surgical pediatry, Hospital for children, CHU, Toulouse

Olivier ziegler, Metabolic diseases, Hospital Jeanne d'Arc, Dommartin Les Toul

Hearings

Elisabeth feur, General Council of Val-de-Marne, Créteil

Philip james, IASO/International Obesity Task Force Offices, London

Pierre levy, LEGOS, University Paris Dauphine, Paris

Scientific and editorial coordination

Fabienne bonnin, Scientific associate, Inserm collective expertise center, Faculty of medicine Xavier-Bichat, Paris

Catherine chenu, Scientific associate, Inserm collective expertise center, Faculty of medicine Xavier-Bichat, Paris

Jeanne etiemble, Director, Inserm collective expertise center, Faculty of medicine Xavier-Bichat, Paris

Anne-Laure pellier, Scientific associate, Inserm collective expertise center, Faculty of medicine Xavier-Bichat, Paris

Bibliographic assistance

Chantal rondet-grellier, Documentalist, Inserm collective expertise center, Faculty of medicine Xavier-Bichat, Paris

Prevalence of adult overweight and obesity

Individual corpulence measurement is an essential biometric parameter. It is appropriate to distinguish between the overall indices that, for each gender, are only a function of body weight (W), height (H) and possibly age, from the combinations of more specific anthropometric measurements (skinfolds, circumferences, diameters, etc.) designed to characterize certain characteristics of body composition (fat mass, adipose tissue distribution, etc.). The universally used overall index is the Quetelet index or body mass index (BMI = W/H²).

The generalized use of the BMI as a body mass indicator, in particular in epidemiology, is due to its great simplicity of determination together with two properties that have been approximately verified on adult populations. BMI is independent of the subject's height and fairly strongly correlated (r = 0.6 to 0.8) with fat mass. However, BMI has a low individual predictive value. It is more appropriate for population studies than for clinical use. The mean BMI of a population and the percentage of subjects with BMI values greater than certain cutoffs enable characterization of corpulence distribution in the population. Thus, by convention, the proportion of subjects considered overweight is the proportion whose BMI exceeds the cutoff of 25 kg/m² while those considered obese exceed 30 kg/m². Finer categories have been proposed (Visscher et al., 2001) but incorporate the two cutoffs systematically used today. The two prevalences obviously depend on the population under study and particularly on age and gender. It should be stressed that those definitions, which are based, as will be seen, on epidemiological observation, do not reflect natural subpopulations and are to be treated with caution at individual level.

The prevalence of excess weight and obesity in adults in France has markedly increased over the last ten years.

The ObEpi survey conducted by telephone in 1997, 2000 and 2003 (Charles and Basdevant, 2003) showed that the prevalence of obesity increased from 8.2 to 11.3% while overweight subjects (thus including obese subjects) increased from 36.7 to 41.6% of the French population aged over 15 years. The trend exists for all age groups, but the mean annual rate of increase in the frequency of obesity would appear to be higher in the age groups 25–34 and 35–44 years (of the order of 8% per year).

An annual survey employing similar methodology and conducted on the US population aged over 18 years (Mokdad et al., 1999) showed a comparable rise in reported obesity, but a rise which began much earlier, since, in the period 1991–1998, obesity prevalence increased from 11.7% for men (12.2% for women) to 17.7% (18.1% for women). The prevalence of obesity in France in 2003 was thus the same as that in the United States in 1991. In the United States, the increase also affected all age groups but was relatively more marked for the age group 18–29 years (of the order of 10% per year).

Repeated epidemiological surveys with measurement of the weight and height of subjects in representative national samples are only available for a few countries. The Nhanes series of surveys in the United States showed an increase in the prevalence of overweight and obesity that has been particularly marked since the start of the 1980s (Flegal et al., 1998 and 2002). The frequency of obesity in people aged over 20 years increased from 13.4% in the 1960s (overweight: 43.4%) to 15% in the 1980s (overweight: 46.2%), then to 30.5% in 1999–2000 (overweight: 64.5%).

In contrast, in Europe, a comparable relative increase only emerged in the 1990s: 10.1% obesity in 1998 in The Netherlands vs. 5.9% in 1988 in subjects aged 19 years and older (Hulshof et al., 2003). The regional representative samples of the Monica project showed high levels since they targeted the age group 35–64 years for which the BMI is on average the highest (Seidell et al., 2002). In Western Europe, the mean prevalence of 15% for the first survey (1979–1985) increased to 18% ten years later (1991–1996). For example, 20.2% obese and 61% overweight subjects were observed in Finland in 1992 (Pietinen et al., 1996) vs. 16 and 58.2%, respectively, in 1982. The mean prevalences in the three French regions targeted by the project (Lille, Strasbourg, Toulouse) were 17 and 18%, respectively (Marquès-Vidal et al., 2004) and therefore had not changed substantially between the two periods. This is compatible with a perhaps rather later increase in obesity in France than in other European countries and an even later increase relative to the United States.

A few remarks will be formulated on the interpretation of that particularly consistent set of results.

The increase in the prevalence of obesity in Western populations indicates that an increasing proportion of subjects have a high fat mass. Although the phenomenon is observed at all ages, the trend appears associated with more marked fat mass increases, particularly at the start of adulthood. Few representative data are available for direct confirmation of the trend but it is to be observed that, in the ObEpi survey, the subjects' self-measured waist circumference increased, on average, from 84.6 cm in 1997 to 86.2 cm in 2000 and 87.2 cm in 2003, equivalent to an annual relative increase of 5%.

The increase in the proportion of obese or overweight subjects was accompanied in all cases by an increase in the mean BMI of the corresponding adult population. The increase is thus largely secondary to changes affecting all the population rather than the particular behaviors of subjects with a high BMI (Silventoinen et al., 2004). However, certain fine analyses show that the general effect of increasing corpulence is not the only mechanism (Pietinen et al., 1996), suggesting that the profile of the BMI distribution in the population is changing with an increase in variance and skewing toward high values.

In France, the proportion of military service recruits who were overweight or obese also constantly increased over the period 1987–1996, from 11.5 to 16.5% and from 1.5 to 3.1%, respectively, while height continued to increase (Salem et al., 2000). This suggests that the increase in the body weight of 19-year old recruits, secondary to the secular trend towards an increase in height, was accompanied by a supplementary weight gain that could already be measured at the end of adolescence. It is thus remarkable that the increase in the prevalence of obese and overweight adults was also observed in children and adolescents over the same period (Lobstein et al., 2004).

Prevalence of childhood overweight and obesity

A simple indicator of corpulence associated with excess fat mass is more difficult in children than in adults since, in children of a given age, BMI is positively associated with height. The correlations observed between BMI and direct estimations of fat mass are generally smaller and depend on the age, gender and pubertal status of the children. However, for high values, i.e. for the detection of obesity, the sensitivity and specificity of the BMI are considered satisfactory (Mast et al., 2002). Despite those reservations, it was considered useful to retain the same body mass index for children, in particular at the epidemiological level. A supplementary step in the standardization of the expression of overweight and obesity in children was made in 2000 by the International Obesity Task Force (IOTF) which proposed: first, replacing the BMI cutoffs defined on the basis of distributions specific to each population by those for a population common to a set of countries; secondly, defining the percentiles corresponding to the cutoffs for each age as those yielding an overweight and obesity frequency at age 18 years defined by the cutoffs of 25 and 30 kg/m², respectively. Those are the universal cutoffs for adults (Cole et al., 2000).

The demonstration of a recent increase in the prevalence of childhood obesity in France and in other Western countries (earlier in the United States) has been well documented (Rolland-Cachera et al., 1992; Lehingue et al., 1996) and reported in the Inserm collective expert review 'Obesity, screening and prevention in children' (2000). Table 1.I complements those data without repeating them. The table is restricted to those studies having used the IOTF definitions, enabling better comparisons. In the interest of simplification, the frequencies have been reported for both genders together.

Table 1.I

Prevalence of overweight and obesity in children by age group as per the IOTF definitions (Cole et al., 2000).

The results observed in France were particularly consistent and show, over the decade 1990–2000, a systematic increase in prevalence, which was relatively greater for obesity than for overweight. The increase over that period was apparently less marked than in countries such as the United Kingdom and Australia. The difference compared to American children is striking since the French rates in 2000 were approximately the same as those observed in the United States at the start of the 1980s. The 30% overweight prevalence for American children aged 6 to 8 years in 2000 may be compared with the European rates in various surveys conducted on 7- to 11-year olds at the end of the 1990s (Lobstein et al., 2003a). The difference is of the same order for Mediterranean children (31 to 36% in Greece, Spain and Italy) but ranges from 12% (The Netherlands) to 20% (United Kingdom) in Northern Europe and was 19% for France.

Overall, the increase in childhood BMI over the 1990s was observed for all age groups and in both boys and girls. The relative increase in the prevalence of obesity may differ in certain groups but the between-study results are in that respect very variable.

In line with the findings in 19-year old recruits, the secular increase in the height of children was pursued over that decade. In consequence, it may be considered that a small proportion of the increase in corpulence may not be due to an increase in fat mass. However, several studies of the mean adiposity of children of a given age (directly measured) showed that the parameter increased in parallel with their body mass index over the same period. Deheeger et al. (2004) showed that the increase in overweight prevalence (97th percentile), children aged over 6 years born in 1985 vs. those at the same age born in the years 1953–1959, was accompanied by an increase in skinfold thickness and subscapular/tricipital fold ratio indicating both an increase in fat mass and a more android change in its distribution. McCarthy et al. (2003) showed a parallel increase in waist measurement and BMI in adolescents aged 11–16 years in two national surveys in the United Kingdom conducted in 1977 (1987 for girls) and 1997.

In short, an increase in overweight and obesity prevalence is known to have occurred in the French population over some 10 years, as was the case in all Western countries, but the onset was much later than in the United States. The current prevalences for children, adolescents and adults may be considered intermediate with respect to those of other countries but markedly lower than those for the US population. Interpreted as essentially reflecting an increase in fat mass, in terms of relative value, the change does not seem exhibit major between-age-group differences and thus does not appear to depend on birth generation. This suggests that the causes largely reside in the time period itself. Numerous population obesity studies have thus particularly addressed the associations between overweight/obesity and the lifestyle, socioeconomic category, cultural habits, and other characteristics of the subjects constituting the population.

Obesity, overweight and socioeconomic factors

In the ObEpi survey, the prevalence of adult obesity differed between regions with the highest prevalence in the North and in the Paris area (Charles and Basdevant, 2003). However, the increase over the period 1997–2003 was more marked in the Paris area and Mediterranean region. The result is to be compared to the distribution of overweight recruits in 1996: overweight recruits had been more frequently from the North and the Mediterranean regions since 1987 (Salem et al., 2000). The overweight frequency also falls with the size of the administrative unit ('commune') of residence. This finding was first observed in 1987 and is doubtless associated with differences in corpulence depending on socioeconomic category. Thus, in the ObEpi survey, in 2003, obesity was 2-fold less frequent in managers and the liberal professions (8.5%) than in craftsmen and tradesmen (16.1%). It is remarkable that the increase in the prevalence of obesity over the period 1997–2003 affected all the socioeconomic categories in a similar manner. Parallel results were observed with another indicator of social status: educational level. The frequency of obesity was 20% in subjects with primary education only and 6% in those with higher education. The increase in obesity since 1997 is once again systematic, irrespective of the educational level considered. Socioeconomic category and educational level are associated with obesity prevalence, independently of each other, in the population of Seine Saint-Denis, for which a low income is also associated with obesity (La Rosa et al., 2003). That finding is not, however, systematically encountered in the literature. In the 1996 Health Survey in the United Kingdom, educational level was the most important factor. The social category effect disappeared when educational level was taken into account (Wardle et al., 2002). The marked increase in obesity and overweight in Austrian recruits over the period 1985–2000 was observed irrespective of educational level and educational level was confounded by height, since recruits with a higher educational level were both taller and had a lower BMI (Kirchengast et al., 2004).

Obviously, numerous other socioeconomic indicators have been studied and the results obtained for overweight and obesity systematically point in the same direction in European populations. Comparison of 8 indicators in a population of Helsinki city employees showed that having had economic difficulties in childhood and currently having economic difficulties seems particularly decisive with respect to the risk of obesity after adjusting for the other more conventional indicators (Laaksonen et al., 2004).

The particular status of the US adult population is noteworthy in this context: the association between a low educational level and the frequency of obesity, very marked in the 1971–1974 Nhanes survey, underwent gradual attenuation and disappeared completely in the 1999–2000 survey (Zhang et al., 2004). Currently, obesity, which is so frequent in the United States (overall adult prevalence: 30% in 2000), appears to be developing in an equivalent manner in the various social classes and over the various ethnic origins suggesting a greater homogenization of living conditions, or at least those that contribute to individual susceptibility to weight gain.

It is remarkable that, over the same periods, the populations of developing countries also experienced, overall, an increase in the frequency of obesity. In contrast, the differences between the population groups with different educational levels increased: those with a low educational level had higher rates than others. This was more marked, the greater the economic development of the country (Monteiro et al., 2004).

It is not surprising that in France, as is the case in many Western countries, the frequency of childhood overweight and obesity differs depending on the parents' socioeconomic levels. In the 1998–1999 INCA survey cited above, the overweight frequency in children aged 3–14 years ranged from 7% in the children of parents who were managers or employed in the liberal professions to 25% in the children of unemployed people. With regard to children aged 10–11 years, a study of primary school children (class: CM2) over the school year 2001–2002 (Labeyrie et al., 2004) demonstrated similar differences (13 vs. 31%). In children aged 14–15 years (class 3 in 2001–2002), overweight prevalence ranged from 11% (managers' children) to 22% (unskilled workers' children), while the obesity rates were 1 to 7%, respectively (De Peretti et al., 2004). A more important role of the mother's educational level than that of the family's financial resources in adolescents aged 12 years has been suggested (Klein-Platat et al., 2003). In children aged 12 to 13 years (class: 5), in the North of France, Romon et al. (2005) observed an increase in overweight and obesity prevalence between 1989 and 1999 that affected all socioeconomic parental categories except managers and liberal professions. For the latter, the prevalences did not increase. Those results do not seem to have been confirmed in other populations (Toschke et al., 2005).

Of course, several studies have investigated whether the association between child BMI and parental socioeconomic indicators was independent of the association with one or two overweight parents. The study by Lang-Nase et al. (2002) of a sample of German school children aged 5–7 years showed that each of the two factors had its own effect. The specific effect of the child's living conditions may be associated with a more sedentary lifestyle, less physical exercise, inferior diet, etc., pointing to the essential components of the etiology of overweight and obesity at population level. Those components will be analyzed elsewhere in this study.

Public health consequences associated with obesity and overweight

The recent increase in the prevalence of obesity described above concerns all the population irrespective of age, i.e. in France several million men, women and children. The scale of the analysis of the consequences of the trend is thus clearly the public health scale. However, it should not be overlooked that the most severe obesity is associated with individual health problems that require management by specialist physicians. Such cases may therefore be considered morbid obesity. There is thus a medical approach to morbid obesity that aims at reducing, as far as possible, the excess fat mass and managing the most immediate consequences in the form of visceral, functional and psychological complications. In the context of health policy, the clinical and public health approaches are thus complementary with the latter attempting to restrict the longer term consequences of non-massive obesity, which is much more frequent. Those consequences can only be dealt with at the population level by addressing the health risks they induce. Epidemiological knowledge plays an essential role in that field. The epidemiological findings and their limitations are briefly described below.

Other complications

The consequences of obesity are not restricted to metabolic and vascular diseases and neoplasms. The consequences affect other organs and involve diseases with important functional implications (respiratory diseases, musculoskeletal diseases, etc.). Table 1.II summarizes the main causes of morbidity in obese subjects.

Table 1.II

Principal complications of obesity.

Corpulence and mortality in the adult population

Although the results observed are sometimes variable and the mechanisms have yet to be elucidated, obesity seems associated with a one third increase in the overall cancer mortality rate (for men) and a one half increase (for women) (Garfinkel, 1986). Once again, it would appear that the excess fat mass and its distribution are causally involved. However, associations between cancer mortality (particularly that associated with alcohol and smoking) and a low body mass index (< 20 kg/m²) have also been reported, suggesting a possible role of lean mass in the development of certain forms of cancer (Oppert et al., 2002).

In most of the cohort studies published to date, the overall adult mortality of men and women is a convex function of the corpulence determined by BMI, confirming the relationship initially observed in populations consisting of insurance company customers (Troïano et al., 1996). The J or U shape of the function varies depending on numerous characteristics of the populations studied. The excess mortality observed with a low BMI (e.g. less than 21 kg/m²) is greater (U form) for subjects aged over 50 years, smokers and ex-smokers, with a history of diseases, than in other subjects, for which the function has a J profile (Calle et al., 1999).

In all cases, the overall mortality rate rises with BMI when the latter has exceeded an approximate cutoff of 28 kg/m². The very elderly (over 85 years) would appear to constitute the only segment of the population for which the relationship has an L form (Stevens et al. 1998).

By way of an example, figure 1.1 shows the mortality plot for the Norwegian population, men and women aged 50 to 64 years, in 1960–80 (Waaler, 1984).

Figure 1.1

Relative risk of total mortality for women and men aged 50–64 years in the Norwegian cohort as a function of body mass index. The reference group was the corresponding whole population (after Waaler, 1984).

For each age, there is thus a very wide range of BMI values associated with low overall mortality. The overweight cutoff conventionally defined as 25 kg/m² is only the limit of the range for young subjects (less than 30 years). The cutoff is rather 28 kg/m² for subjects aged over 50 years. In contrast, an increase in overall mortality for a BMI greater than 30 kg/m² (conventional obesity cutoff) and for a BMI less than 20 kg/m² was observed overall in all the studies.

The interpretation of the excess mortality systematically observed in subjects with a low BMI has been the subject of considerable speculation and at least partially reflects confounders induced by unfavorable factors frequently experienced by low-weight adults at some time in their lives: poorer general health, intercurrent diseases, smoking, etc. However, taking those factors into account does not appear to totally explain the excess mortality (Mikkelsen et al., 1999). For example, excluding from the analysis deaths occurring very early relative to BMI determination (e.g. within 5 years) only slightly modifies the relative risk estimates.

The limitations of BMI as an indicator of obesity or thinness are thus clear. In order to advance further, it is undoubtedly necessary to take individual body composition into account.

The Paris Prospective Study (PPS) showed that overall mortality in man increased regularly with the iliac/thigh circumference ratio. It does not with BMI (Cloarec-Blanchard et al., 1990). The mortality risk may therefore be expressed in terms of fat mass and lean mass (Oppert et al., 2002). Similar results have since been obtained, in particular in women, with the waist/hip circumference ratio (Folsom et al., 1993). This is shown by the relative risks displayed in table 1.III.

Table 1.III

Relative risks of total mortality as a function of body mass index distribution quintile and a body composition index in the male population (43–52 years) of the Paris Prospective Study (PPS) (Cloarec-Blanchard et al., 1990) and in the female (more...)

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Genetic determinants

Genetic susceptibility was demonstrated in studies conducted on monozygous twins who showed a great similarity in weight gain when breast-fed in the course of overnutrition studies (Bouchard and Tremblay, 1997). However, the familial nature of obesity is the reflection of combined factors that are genetic, but also intra-familial environmental factors (including intrauterine factors, breast-feeding, etc.). Those factors intervene in addition to the extra-familial environmental factors specific to each individual. It is difficult to determine the specific contribution of each factor. On the basis of some fifty studies of the families of twins concordant or non-concordant for obesity, Bouchard et al. (2003) concluded that genetic factors contributed 25 to 40% of the variations in the subjects' weight and fat mass. Intensive research on obesity genes has been conducted in recent years. Over 400 genes, markers or chromosomal regions have been shown to be related to obesity (Snyder et al., 2004). However, only 6 monogenic mutations have been shown to be responsible for obesity in less than 150 subjects. Those discoveries (Clément et al., 1998; O'Rahilly et al., 2003) furthered our knowledge of the mechanisms of obesity but, outside of those exceptional cases, obesity appears to be a complex genetic trait. However, there is an increase in the risk of obesity in children whose parents are overweight, particularly if both parents are overweight (Magarey et al., 2003). However, it is clear that the current increase in obesity incidence is not due to a change in the genetic characteristics of the populations considered but rather consists in an interaction between predisposing genotypes and behavioral and environmental changes.

Early determinants

Recently, it was suggested that early environmental factors ranging from fetal life to the first years of extrauterine life could influence health in adulthood. With regard to obesity, a relationship between birth weight and adult BMI was evidenced. Several studies have shown a relationship between high birth weight and obesity in adulthood (Whitaker, 2004). Similarly, obesity is found in children whose mothers had gestational diabetes (Silverman, 1998). It would appear that the fetal hyperinsulinism encountered in those contexts is responsible for changes in body composition and even adaptation of pancreatic function, generating hyperinsulinism. Relationships have also been evidenced between low birth weight and central obesity and hyperinsulinism in adulthood. It would appear that fetal malnutrition during the 2nd and 3rd trimesters of pregnancy may modify gene expression by an epigenetic process and result in a saving phenotype with harmful effects in adulthood and emergence of a metabolic syndrome (Gallou-Kabani and Junien, 2005). New studies are required to confirm those hypotheses. Data from animal studies and epidemiological studies such as the Eden¹ study, currently ongoing, should enable elucidation in that field (Charles, 2005). The aim of the Eden is to identify pre- and early post-natal factors (exposure and maternal health during pregnancy factors, intrauterine fetal development, infant's status at birth and in the first few months of life) influencing the child's subsequent development and health. A further aim is to elucidate the mechanisms of those relationships. The study should enable a clearer understanding of the importance of early determinants with respect to individual health, in particular with regard to the numerous environmental factors that influence health during childhood and adulthood.

Diet during the neonatal period also seems to be involved in the subsequent time course of body weight. The protective effect of breast-feeding with respect to childhood obesity was first reported by Kramer in 1981. Since then, a number of studies have been published and reviews have been conducted. In the meta-analysis by Arenz et al. (2004), 954 studies were identified. Only 9 were selected after ruling out confounding factors (birth weight, parenteral weights, socioeconomic factors, etc.). The meta-analysis enabled comparison of infants breast-fed for more than 6 months and non-breast-fed infants. It showed a weak but certain protective effect of breast-feeding with respect to childhood obesity. Four studies showed a dose-response effect of the duration of breast-feeding on the prevention of obesity. Multiple factors would appear to be involved in the protective effect and are still under discussion: enhanced learning of satiety by breast-feeding, role of the composition of breast-milk (protein content, type of fatty acids, leptin), less insulin secretion post-breast-feeding, etc.

Recently, the role of the type of fatty acids in adipose tissue development was demonstrated. Fatty acids of the n-6 series are potent promoters of adipogenesis in vitro and adipose tissue development in vivo (Ailhaud and Guesnet, 2004). Fatty acids of the n-3 series such as EPA, DHA and conjugated linoleic acids (CLA) decrease pre-adipocyte proliferation and adiposity in rodent models (Azain, 2004). These factors thus appear to be important determinants of obesity development. However, the nature of breast-milk fatty acids depends on the maternal diet and the fatty acid composition of milk formulas has evolved over time. It is therefore difficult to determine the influence of those changes but they are probably parameters that will need to be taken into account in the future.

Weight during childhood is a predictor of weight during adulthood. The BMI at age 6 years appears in particular predictive of the BMI at 20 years. BMI at 6 years has more influence than parental BMI, although the overweight risk increases with parental weight (Magarey et al., 2003). It is noteworthy that the father's and mother's weights seem to have a different influence on the child's weight. Maternal BMI is a stronger determinant with respect to childhood and adolescent BMI while paternal BMI has a greater influence on adipose mass distribution (Heude et al., 2005). The time course of BMI over childhood also has a predictive value. BMI re-increases in a physiological manner after a nadir between age 4 and 7 years. This is known as the adiposity rebound. Rolland-Cachera et al. (1984) showed that an early rebound was associated with an increased risk of obesity. This finding has been contested by certain authors who have shown that crossing the BMI percentile plot is associated with an enhanced risk of obesity irrespective of age (Cole, 2004). The data show the value of monitoring weight gain and height over childhood. It would appear that a risk profile may emerge during that period of life. The profile associates an extreme birth weight, absence of breast-feeding, an unfavorable course of body mass index and parental obesity. The conjunction of several of those factors is to be taken into account in defining targets for action.

Food intake and dietary behavior

Food intake is one of the fundamental determinants of obesity. Irrespective of genetic susceptibility, weight gain can only occur if there first exists a sustained unbalance of the energy balance and hence an excess of food intake relative to energy expenditure. However, in addition to meeting the subject's energy requirements, eating involves social, cultural and emotional aspects of everyday life. Adults and children eat, in part, because they are hungry, but also because drinking and eating are pleasant and an integral part of family life, celebrations and various social events. Food is for many people an important component of their well-being and a compensation for psychological aggression. It is thus completely unrealistic and would be a total failure to base obesity prevention operations on food energy composition considerations only, without taking into account the social, economic and affective dimensions of eating. Moreover, while the toxic nature of cigarettes and alcohol is not open to debate, the concept of good or bad foods is not the subject of a consensus, even in purely nutritional terms.

In reality, the nutritional qualities of a food largely depend on the quantities eaten, the mode of consumption and the other foods eaten at the same time. The whole diet conditions the quality of the diet with respect to its energy content and the macronutrient distribution. Nonetheless, some recommendations may be formulated with regard to the quality of the diet as has been done in France in the 'Recommended dietary intakes for the French population' (table 2.I) (Martin, 2001). The energy density of foods is also to be taken into account (Simon, 2003). Subjects adjust their ingestates more on the food volume than on the calorie intake. It will thus be understood that a diet with a high energy density results in high energy intakes while a diet with a low energy density procuring few calories in a large volume induces satiety and results in a lower energy intake. The energy density of foods largely depends on their lipid content. Lipids procure 9 kcal/g while carbohydrates and proteins only procure 4 kcal/g. Water, by increasing the weight and volume without changing the calorie content, and fiber content also enable a reduction in the energy density of foods. The quantity of foods eaten also depends on their palatability. The palatability of a food is its pleasantness. It depends on the sensory characteristics of the food: appearance, taste, odor, texture, etc. Palatability promotes excess energy intake, particularly since palatability and high energy density are frequently associated. It is noteworthy that the attraction for fat and sugar and the intensity of the pleasure experienced when palatable foods are eaten varies between individuals and are in part genetically determined.

Table 2.I

Frequency of food intakes enabling adequate macronutrient intakes, particularly with respect to folic acid (1), calcium (2), iodine (3), iron (4) and vitamin C (5) (after Martin, 2001).

An increase in the consumption of sweet beverages is undoubtedly an important change in the modern diet. Beverage intake is subject more to fluids regulation than to energy regulation. The speed of ingestion and the absence of chewing are factors that do not promote satiety. In that context, the current sweet beverage consumption increase, particularly by adolescents, is worrying with respect to the development of obesity. The role of fat foods vs. carbohydrate foods in the genesis of obesity has been greatly discussed in the literature (Willett, 1999). Foods with a high lipid content due to their high calorie density, generally good palatability and low energy storage cost are potentially the foods that most generate obesity. However, a decrease in fat intake has been reported in various countries (United States, Finland, Great Britain) although the prevalence of obesity is increasing (Prentice and Jebb, 1995; Fogelholm et al., 1996). Those data nonetheless need to be tempered by the fact that populations have become sedentary, reducing their energy requirements. Few studies have concomitantly addressed the amount of physical exercise and food intake. It is noteworthy that despite the increasing availability of low-fat products and the recommendations with respect to decreasing the fat content of the diet, energy intakes remain high. It cannot be excluded that the campaigns stigmatizing fats have led some people to consume low-fat products without restriction. Some of those products have a high energy density and palatability (Simon, 2003). This draws attention to the potential danger of campaigns stigmatizing one type of food when obesity has multiple determinants. It is the total dietary calorie intake that is important, not the nature of the foods. Excessive carbohydrate intake can also be harmful, particularly when the carbohydrates are added sugars which increase the energy density of foods. A sweet taste contributes to a hedonic quality of foods, particularly when the sugar is associated with fats. Passive overconsumption may result. Afssa thus recommends (2004) decreasing the consumption of added simple sugars. The report also stresses that it is preferable for carbohydrates to be eaten in solid rather than liquid form and in the context of structured meals rather than between meals. The change in eating habits plays an indubitable role in the development of obesity. The ubiquity of food offer and particularly the availability of ready-to-eat foods compromise the structure of eating behavior and the ritual aspects of meals. The Inca study² (Afssa, 1999) shows that France has not been spared from this disintegration of the traditional model. In addition, the role of increasing portion size in the inflation of individual energy intakes should not be overlooked.

Adipose tissue storage capacity

Adipose tissue is responsible for the storage of energy reserves. The inflation of adipose reserves which characterizes obesity initially results from an unbalance between energy intake and output. This unbalance may also be promoted by primary anomalies of adipose tissue, which has become particularly 'gifted' at storage due to cell anomalies. Adipose tissue is of an exceptional plasticity. Throughout life it remains capable of growth. The number of adipocytes can thus markedly increase. The increase in the number of adipocytes results from the adipogenesis process, which involves a process of stem cell proliferation and differentiation into adipocytes. Numerous intrinsic or extrinsic molecular and cellular factors are involved in the proliferation of adipose tissue. The complex process is controlled by various signals modifying the activity of the transcription factors identified by molecular biology. According to the 'critical size' hypothesis, there is a maximum cell size. Thus, the differentiated adipocyte takes up triglycerides until it reaches the critical size. It then 'recruits' a new pre-adipocyte. An increase in the number of adipocytes, in other words, hyperplasia, may thus occur. The number of adipose cells continues to increase if energy storage is necessary because of a positive energy balance. The cells remain available for de novo storage. The hyperplasia seems to be irreversible. This explains why, after a certain amplitude and duration, return to the initial weight is not possible. It is impossible to maintain adipocyte size below a certain value without triggering all the mechanisms which reconstitute fat mass. The minimum fat mass that it is possible to achieve is limited by the number of adipocytes. If the number is high, either constitutionally or subsequent to recruitment of new cells during weight gain, it is difficult to reduce the volume of the fat mass below a certain threshold (except by permanent dieting). In other words, obesity may result from or be promoted by primary anomalies of adipose tissue, of genetic origin or acquired (questions are being asked with regard to the substances in the body, diet or environment that may promote obesity independently of calories, in particular during the perinatal period). The pathophysiology of obesity is proving increasingly complex and heterogeneous, varying markedly between individuals.

Physical activity

The other important part of the energy balance is energy expenditure. Although physical activity is not the most important component of total energy expenditure (the most important component is resting metabolism, which essentially depends on body weight, height, age and gender), it is the part most subject to modulation. Each individual's level of physical activity depends on various parameters related to his/her personal, environmental and also genetic characteristics (Wolfarth et al., 2005). It should also be understood that the energy balance is an integration over a very long interval. A minor dysequilibrium in the balance of the order of 100 kcal/d results in annual weight gain of 5 kg and can thus engender obesity over time (Jéquier, 2002). In addition to the energy consequences, it is now recognized that a low level of physical activity is associated with an increase in the overall mortality risk, cardiovascular morbidity and mortality, and an increase in the risk of hypertension, an increase in the risk of type 2 diabetes mellitus and an increase in the risk of certain forms of cancer, together with an increase in states of anxiety and depression (Oppert, 2003). The current recommendations for physical activity are 30 minutes of physical exercise, such as fast walking, daily. Those recommendations target overall health and particularly the cardiovascular risk. They are not however specifically adapted to the prevention of weight gain and obesity. In France, few data on the degree of physical activity of the population and its time course are available. The Suvimax study showed that 10% of men and 12% of women take no physical exercise and almost half the population does not achieve the recommended level of exercise. Changes in lifestyle and particularly technological progress have decreased the energy expenditures related to work, housework and traveling. Despite the increase in leisure time, the overall tendency is toward a reduction in physical exercise making physical inactivity a veritable public health problem (Prentice and Jebb, 1995; High committee of public health, 2000). It is noteworthy that the time spent on inactive occupations such as watching television and playing video games is markedly increasing. The calculations necessary to determine the level of physical exercise required to prevent weight gain show that that level is 1.5- to 2-fold higher than the above recommendations (Fogelhom and Kukkonen-Harjula, 2000; Oppert, 2003). The type of physical exercise able to have an effect with respect to preventing obesity is still under discussion. In particular, should the total energy expenditure through exercise or the intensity of the exercise be addressed? In addition to promoting physical exercise to combat obesity, it would appear of value to add measures relating to the reduction of the sedentary lifestyle. This will necessitate developing new markers of sedentary lifestyle, which cannot simply be considered the time spent in front of the television. It is important to take into account not only behavior with respect to physical exercise but also dietary behavior and other behavioral patterns such as alcohol consumption and smoking. Enhanced understanding of the groupings of those various types of behavior and particularly their determinants at both individual and collective level is a major issue with regard to defining strategies to combat obesity (Oppert, 2003).

Psychological and social factors

Eating is at the center of decisive processes in the psychological development of the child. It is therefore not surprising that psychological factors play a decisive role in the genesis of certain forms of obesity associated with dietary behavior disorders. The psychological factors influence eating behavior, which is very sensitive to emotions and stress. Anxiety and/or depression may also induce compulsive eating.

The nutritional, familial and social environment and economic changes are all decisive factors. The role of the evolution of the food industry at all levels needs to be stressed: intensive production, facilitated distribution, simplified preparation, disordered consumption. The current nutritional situation is unprecedented. We must learn how to adapt to plethora when we are programmed to withstand famine.

At the source of the reduction in energy expenditures lie the change in clothing, heating, transport, manual work, food-obtaining behavior, development of services, reduction in the 'energetic cost' of consumption activities and progress in communication. While leisure occupies more of our time, relaxing physical exercise remains unpopular. Passive leisure activities (television and others) predominate, in particular due to urbanization and its material, psychological and social consequences. There is, in fact, a close relationship between the number of hours spent in front of the television and the prevalence of obesity.

Prospects and orientations

In the light of those determinants, targets for obesity prevention may be singled out.

We clearly cannot change the genetic aspects although they intervene at various levels not only on the energy aspects but also on behavior with regard to eating and physical exercise. With regard to early determinants, more research is needed to elucidate their real importance. It would appear that the mother's nutritional status during pregnancy influences the outcome for the future child and its state of health. Close nutritional monitoring of the pregnant women is thus essential. Breast-feeding would seem to play a positive role justifying promotion of breast-feeding, not that breast-feeding alone will have an important impact on body weight on the population scale. In that context of early diet, it is important to monitor the time course of milk fatty acids, be the milk breast-milk or an infant formula, since fatty acid type seems to be important with respect to adipogenesis. Lastly, regular monitoring of children's weight and height should enable detection of risk situations for which early interventions are justified.

The campaigns intended to modify dietary behavior should not overlook the social, affective and cultural components of eating. Campaigns should be more targeted on the overall mode of eating with a view to restructuring meals and restoring their ritual nature rather than stigmatizing a food or nutrient. The food industry's efforts should target reducing portion size and developing low-energy density foods. The challenge will be to retain the palatability of such foods and market them effectively. Only such changes in the food offer will enable the population to be 'passively' oriented toward a healthier diet. The changes in the modes of consumption will not, in themselves, be effective. Global strategies incorporating combating the sedentary lifestyle and promoting physical exercise are also to be implemented. Further studies are required to optimally define the type of physical exercise (duration, intensity) that is most effective in combating weight gain. Nonetheless, the population's adoption of the current recommendations would already be a considerable step forward. Once again, it is necessary to privilege environmental changes which make access to physical exercise easier or access to inactivity more difficult…

In conclusion, the determinations of the development of obesity are increasingly well known and are complex and mutually interact. It would be a mistake to believe that a single factor is causal or predominant. Strategies enabling changes in the environment and leading to easy adoption of 'health' behaviors may be successful. However, they necessitate the involvement of a large number of societal players: politicians, town planners, economists, food-industry professionals, food-distribution professionals, restaurant managers, teachers, trainers, physicians, etc.

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Economic analysis of the development of overweight and obesity

The conceptual framework of the economic analysis is particularly suited to analysis of the effects of environmental changes (and particularly costs) on individual behaviors. For some years, studies using economic concepts have been implemented with a view to understanding the development of obesity and structuring the interventional actions.

Economic criteria for public intervention

The state's role in ensuring the safety of food supplies and the health safety of foods is rarely called into question. In contrast, state intervention at individual dietary choice level may be questionable. The increasing demand for public intervention to combat the development of obesity has thus given rise to a debate on its economic justification. For the economist, public intervention is justified when the market is inefficient or distorted. In the case of food choices, asymmetric information and negative externalities are two obvious reasons for intervening. There are two further reasons, which are not only economic: the defects of rationality and equity.

Economic measures in the prevention of obesity

It is important to clearly distinguish the analysis of economic obesity prevention measures and the economic justification of those interventions. The latter, as indicated above, stresses the formal criteria for intervention (asymmetric information, negative externalities, defective rationality). It does not take into account the content of the choices nor the objectives pursued by those who make them. In the economic analysis of preventive measures, the objective of improving public health, or equity, is taken as a given and the costs and effectiveness of the various actions considered are addressed.

Economic obesity prevention measures are based on modifying the incitement mechanisms enabling individuals to make their choices. In order to do so, the economist has two levers: price and information.

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Economic approach to the impact of the disease

The economic approach to the disease focuses on the financial or economic impact of a disease by estimating its cost. The difficulties encountered in that approach are, first of all, data availability and, secondly, the need to make pertinent choices with regard to the various parameters that define the perimeters of the costs considered. The cost perimeter depends first on the nature of the costs included in the estimate (medical direct costs, non-medical direct costs and even indirect costs generated by loss of production). Other parameters introduce additional variability, making comparison delicate: the perspective adopted (society, health insurance, etc.), the BMI cutoff used to define overweight and obesity, the time scale selected (from 1 year to the patient's lifetime), the choice between a prevalence or incidence approach, an estimate of the top-down or bottom-up type. With regard to the latter types of estimate, the former gradually reduces all the set of healthcare expenditures to the part attributable to a disease while the second first measures the individual cost by patient type before extending the measurement to the group involved on the basis of epidemiological data.

In France, two studies of that type are available (Levy et al., 1995; Detournay et al., 2000). Both refer to the prevalence of obesity in 1992, defined as a BMI ≥30. The annual direct costs from the point of view of society were calculated.

The first study (Levy et al., 1995) adopted a top-down approach and restricted the cost perimeter to a limited list of diseases partially attributable to obesity. The total annual cost of those diseases was estimated before selecting the proportion of cases attributable (PCA) to obesity as a function of relative risk (RR) (table 4.I). For a total direct cost of all the diseases of FRF 66.1 billion in 1992 (11% of healthcare expenditures), the part attributable to obesity was reported to be FRF 5.8 billion (BMI ≥30), or even FRF 12.1 billion (BMI ≥27). Caution is required with respect to the results due to the heterogeneity of the data sources and other limitations related to the difficulty of estimating pertinent parameters for France (public hospital costs based on the price of a day with the Paris Public Hospital Authority (AP-HP), RR based on international data). The total cost is probably an underestimate given the PCA indicated by WHO in its report on industrialized countries in 2002.

Table 4.I

Diseases attributable to obesity after Levy et al., 1995).

The second study used the bottom-up method to generate an alternative estimate of the cost of obesity in France (Detournay et al., 2000). Using the data generated by the Insee `Households' survey, the study addressed a representative sample of French adults. The cost of obesity was estimated at the individual level by the excess cost method by comparing the healthcare expenditures of the obese population with that of the normal population (18.5 ≤ BMI ≤ 25). The excess cost was then extrapolated to French national level as a function of the ratio between the sample size and size of the French population. The study estimated the mean annual net excess cost to be FRF 911 per obese patient. The excess cost consisted in the gross excess cost related to diseases attributable to obesity (FRF +1.183) from which the lesser cost of other diseases (FRF -972) related to an unexplained lesser recourse to healthcare was deducted. For France as a whole, the net excess cost was thus FRF 4.2 billion (0.7% of healthcare expenditures) and the gross excess cost FRF 8.7 billion (1.5% of healthcare expenditures). Using the reported medical consumption data, known to be very little reliable, on hospital costs, the authors were forced to conduct an adjustment to take into account the obvious under-evaluation of the annual expenditures of the sample population vs. the French population (adjustment coefficient: 1.66).

The French results suggest that the medical cost of obesity accounts for about 1 to 2% of total healthcare expenditures. The results are nonetheless fragile and old and are less than those for other countries. The generally accepted range is from 2 to 7% (2 to 2.5% for Australia, Canada and New Zealand; 3.5% for Portugal; 5 to 7% for the United States). Moreover, the scope and interpretation of the results are far from obvious. What information can be drawn from a comparison with the cost of other diseases? Is the cost that of the treated disease or that of the untreated disease? Can the cost be avoided and if so at what price?

The type of questions raised by disease cost studies explains why numerous health economists are not in favor and prefer to refer to the issue of efficiency. If we nonetheless wish to estimate the burden associated with the disease, an alternative approach consists in the mortality and disability-adjusted life years (DALY) attributable to overweight and obesity. The latter measurement adds the equivalent of the years lost through degradation of quality of life to the years lost by premature death (Gold et al., 2002).

Economic evaluation studies

Economic evaluation studies have very little addressed obesity since the only review is to be found in one synthesis and no article addresses France (Avenell et al., 2004). There are, of course, objective reasons for that, particularly the limited number of therapeutic strategies (medicinal) available and the difficulties inherent in chronic diseases in which long-terms effects cannot be neglected. The objective of the approach is to estimate the cost per year of life gained (cost-effectiveness study) or the cost per QALY³ gained (cost-utility study) for a given strategy vs. another. The approach is two-phase: beginning with the data generated by a randomized, controlled trial, one attempts to evaluate both the costs associated with each therapeutic strategy and its effects measured using an interim result indicator (weight loss, percent reduction in BMI). Secondly, the long-term outcome for the patients are modeled using a final indicator (years of life saved, QALYs).

Several studies have recently been undertaken with a view to short-term evaluation in the context of a clinical trial or care program (Wylie-Rosett et al., 2001; Dzator et al., 2004) or for a surgical strategy (Avenell et al., 2004). An interesting study focused on the second phase of the approach by modeling the cost and effectiveness of a 10% permanent reduction in BMI vs. baseline (Oster et al., 1999). The study estimated that the reduction in the medical costs over the patient's lifetime was between USD 2,200 and 5,300. The reduction in the incidence of strokes was between 1 and 3‰ and the reduction in coronary heart disease between 12 and 38°/oo. Life expectancy increased by between 2 and 7 months.

Combining both components, certain studies have reported a cost per year of life saved or QALY saved whose results are shown in a League Table in the most recent review (Avenell et al., 2004). Differentiation of the patients appears to be of fundamental importance since the cost per year of life or QALY gained was less than GBP 13,000 for numerous strategies (including Orlistat®) for obese patients at high risk while the ratio increased to almost GBP 46,000 for obesity alone with Orlistat®. These results are, however, to be considered with caution due to the hypotheses, which may sometimes be heroic, necessary to model the long-term outcome for the patients.

Lastly, the Who-choice model is worthy of mention (WHO, 2002). Who-choice does not specifically consider obesity but estimates the cost of the DALY avoided by various strategies designed to combat physical inactivity and dietary risk factors (table 4.II). By considering the marginal cost-effectiveness ratio which enables estimation of the additional cost per DALY prevented, it was observed that few of the strategies are of interest. More precisely, all strategies combining nutritional education (and lifestyle education) with other interventions are dominated by other strategies. In other words, they are both more expensive and less effective. Conversely, health education via the media with a view to reducing cholesterol appears a more efficient strategy (lowest ratio value) alone or in combination with legislation to reduce salt intake, possibly together with tritherapy for patients at high cardiovascular risk.

Table 4.II

Cost-effectiveness analysis of various programs addressing dietary risk factors and physical inactivity in the WHO-choice model *.

In conclusion, the economic costs of overweight and obesity are important criteria for health policy deciders. On the basis of the international studies, the minimum estimate for those costs would be 2 to 7% of healthcare costs. The studies quantifying the economic weight of obesity-related morbidity and mortality, although imperfect, clearly confirm that the condition constitutes an important public healthcare issue and is continuing to increase. The economic approach (cost-effectiveness, cost-benefit studies, etc.) also constitutes an essential instrument for the selection of treatment and prevention regimens for the management of obesity. The latter type of study has still not been widely applied in the field of obesity.

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Data sources

Two recent reviews, one addressing randomized obesity prevention trials in children and adolescents (Campbell et al., 2005) and the other the promotion of physical exercise in children and adults (Kahn et al., 2002) are available. Few probative interventional studies, most of which are summarized in the two reviews, have been published with respect to either the prevention of obesity or the promotion of physical exercise and healthy eating habits. But the absence of evidence is not equivalent to inefficacy: high-quality studies are not very numerous (22 randomized studies on obesity prevention of which only 10 aged less than one year) and it is frequently not possible to determine whether the absence of observable effect in certain studies is related to the real inefficacy of the projected operation, to the fact that the operation was not implemented as scheduled, to an excessively short duration of the interventions or to a lack of statistical power due to the small population included or a high lost to follow-up rate (NHS, 2002). Moreover, despite the increasing recognition of the influence of the environment and society on behavior, few interventions have taken that contextual complexity into account.

While randomized, controlled studies are the gold standard for testing clinical and research interventions, the approach is not always feasible, appropriate or ethical on a population scale. In addition, for numerous environmental, political, legislative and societal variables, attentive evaluation of large-scale, rigorous observational studies and ongoing preventive programs and policies enable a number of key questions to be answered. For those reasons, an integral and wider review of the evidence available in the field was implemented with a view to enhancing the pertinence of the information and identifying promising approaches.

In addition to that information, data drawn from the experience generated with other preventive strategies for other public health problems (IOM, 2002 and 2005) such as smoking (CDC, 1999; Yach et al., 2005), road safety (IOM, 2002; Gielen and Sleet, 2003) and the prevention of cardiovascular diseases were used. In the latter field, the cardiovascular disease prevention programs implemented in Finland over the last 20 years (Puska et al., 1998; Puska, 2002) reflect a real public health policy yielding results that have been published in scientific journals.

Various reports and expert reviews have been published by the international organizations, particularly the World Health Organization for the world (WHO, 2003a and b) or for Europe (WHO, 2001 and 2003c). The latter report briefly summarizes the operations or programs implemented in the various European Union Member States. The European guidelines for a healthy diet published by WHO (2000) and various reports funded by the European Union (Eurodiet, 2000; Brettschneider and Naul, 2004) are also available.

Reports and proposals have been compiled by learned societies or associations such as the European Association for the Study of Obesity, which published a report with proposals, in cooperation with the International Obesity Task Force (EASO, 2002). The European Federation of Cardiology Societies made the prevention of childhood obesity a major component of its communication in 2005 and published a report on the `Marketing of nutritionally incorrect foods' in Europe (EHN, 2005).

Reports and plans of action have been published by various countries, particularly the United States (IOM, 2005), Canada (CIHR/CPHI, 2003), Denmark (National Board of Health, 2003), the United Kingdom (NAO, 2001) and more recently Sweden (National Food Administration, 2005). A document published by the University of Sidney in support of the nutritional policy in Australia and New Zealand is of interest in that it classifies the various potential actions on the basis of their probable efficiency (University of Sidney, 2005).

Taking into account the above sets of data, justified by the fact that the obesity epidemic is a public health problem requiring immediate and rapid action, obviously necessitates developing, in parallel, an action strategy based on the information and the appropriate evidence that continues to be generated and accumulated. This is indispensable not only to ensure that the operations implemented elicit significant effects and justify their pursuit, but also to check that the effects are sustainable and applicable on a larger scale or to other populations. It is also necessary to identify the related effects (on the population scale and on the society scale) and to estimate the cost/benefit ratio. For that reason, evaluation is to be a major constituent of any intervention in the field.

Context and conceptual bases

The definition of a preventive program necessitates an analysis of the context with regard to the life of the population addressed. The preventive strategy will also differ depending on the target: all the population, group at risk or subjects already overweight.

Environment, society, lifestyle and obesity

The influence of the social, cultural, physical and political environment on the individual's lifestyle and, in consequence, on the individual's state of health has now been firmly established (Booth et al., 2001; Davison and Birch, 2001; Lobstein et al., 2004). Society has considerably evolved over a few decades and numerous changes - industrialization, mechanization, urbanization, increase in the number of meals eaten outside the home, modification of food offer - have profoundly influenced our dietary habits and our energy requirements. Other changes such as the increasing diversity of populations influence the cultural aspects, methods of food distribution and marketing strategies.

Currently, our society is structured in such a way that individuals frequently do not need to be physically active during a usual day. Not only does urbanization promote reliance on cars but it discourages the use of active means of transport. Access to hiking or cycling trails, parks and leisure areas is frequently made difficult by extensive urbanization and the distances between home and those facilities. For many, it is not possible to remain physically active without strong motivation and marked effort. Concomitantly, the evolving leisure offer (television, video games, etc.) promotes inactive behavior and increases individual vulnerability to weight gain.

In addition, we live in a context of abundant food. Certain characteristics of the `modern' diet - high energy density and nutritional composition, portion size, physical properties, palatability, overabundance and diversity - promote passive over-consumption. The same is true for energy-rich drinks and the commercial trend toward promoting food on quantity rather than on quality. The availability of ready-to-eat, palatable and relative inexpensive foods in all places and at all times encourages food intake in response to determinants other than energy requirements. Moving beyond the characteristics of foods, the growth of eating outside of home, the compromised structure of eating, the simplification of meals and loss of their `ritual' aspects (less time devoted to meals, television during meals) also promote excessive energy intakes. Moreover, due the current commercial offer, food intakes outside of meals and fast food frequently consist in ready-to-eat products with a high energy content or sweet beverages.

Without passing over the contribution of that change in the food system to improvement of certain aspects of health on the population scale (decrease in under-nutrition, infantile mortality and increased life expectancy, for example), it must nonetheless be admitted that the new food availability promotes new public health issues, of which obesity is a prime example.

WHO (2003b) recently classified the factors associated with an increased or decreased risk of obesity on the basis of the quality of the empirical and epidemiological arguments underlying the relationships (table 5.I). It will be noted that, since the table was compiled, studies on portion size have generated results that call for classifying portion size in the probable factor category (Ledikwe et al., 2005).

Table 5.I

Factors liable to increase or decrease the risk of weight gain (WHO, 2003b).

The ecological niche concept

A large number of the social, cultural and environmental characteristics of industrialized countries that populations now consider `normal' also contribute collectively to the increase in obesity. It is now patent that the intrapersonal factors (genetic, biological and psychological) which condition physical exercise and food choices can no longer be considered in isolation but must be incorporated in a complex network of individual, interpersonal and environmental factors (Booth et al., 2001; Kumanyika et al., 2002; Swinburn et al., 2004; Swinburn et al., 2005). More specifically, understanding what makes a subject at risk of gaining weight (and in consequence, the setup of effective preventive strategies) necessitates taking into consideration the context, the `ecological niche' in which the subject lives: familial environment, school and professional environment, but also in a wider sense the housing estate and society (figure 5.1).

Figure 5.1

Determinants of physical exercise and food choices (after Booth et al., 2001; Davison and Birch, 2001).

Thus, the attitudes and lifestyles or consumption of parents, friends, colleagues and, more generally, the social entourage (citizens, but also teachers, trainers, management, healthcare personnel, etc.) influence individual practices. More structural factors such as urbanization policy and public transport, the accessibility and cost of leisure facilities and sports grounds, the availability of facilities that could be used safely, the offers in the workplace are all factors liable to influence an individual's physical exercise. The same applies in the context of schools, the organization and content of physical education or the layout of the playground. Distances and lack of time are the most frequently reported obstacles to physical exercise. The time spent at work and school and traveling also indirectly influences the degree of physical exercise. Similarly, the food offer in school and company canteens, in the workplace and in schools (accessible water fountains, for instance) or in fast-food facilities directly influences choices and modes of food consumption. The cost of products, impact of the media and advertising or regulatory aspects with regard to food quality and restaurants are also to be cited.

Various interventional levels

Preventive actions may be classified by their interventional level. Three levels are usually distinguished: universal or large-scale prevention targeting the population or community as a whole; selective prevention targeting groups at high risk of weight gain; and targeted prevention addressing subjects who are already overweight or at a high risk of concomitant disease (figure 5.2).

Figure 5.2

Preventive action levels (after WHO, 2003a).

The universal approach, whose objective is to reduce the obesity level throughout the population, has been criticized since it also affects subjects who are not concerned by the health problem. Given the high prevalence of obesity and insofar as the approach targets behaviors (physical exercise, food choices) having effects on health independent of their effects on body weight, the universal approach appears justified and constitutes the form of prevention with the highest potential cost-effectiveness ratio.

The objective of selective prevention that targets subgroups of the population at high risk of weight gain is to help the subjects become aware of their problem and provide them with the resources and skills to enable them to achieve more effective control over the factors contributing to the risk.

Targeted prevention if it is restricted to avoiding additional weight gain and the concomitant diseases associated with overweight, is usually based on more intensive individual or small-group strategies.

It should be stressed from the outset that while the levels may be distinguished by the populations targeted and their different short-term objectives, they are nonetheless interdependent: a coordinated and consistent approach at the various levels should enhance the probability of being effective in the long term. Moreover, obesity prevention cannot be totally dissociated from the thinking on obesity management. It is not only a question of avoiding normal subjects becoming obese but also of preventing additional weight gain in obese subjects and promoting weight stabilization in obese subjects having lost weight.

Strategic thrusts: concept of `effort-free' prevention

The prevention of obesity involves both healthy eating behavior and regular exercise with the objective of achieving and maintaining the energy balance at the level of a `healthy' weight. Overall, two types of strategy may be distinguished: those aiming at increasing individual understanding and skills (active changes) and those aimed at modifying the environment by proposing the adoption and maintenance of an active lifestyle and appropriate food choices (passive or `effort-free' changes) for the population. The latter strategies are not restricted to the physical and structural environment but also incorporate the societal, economic, political and legislative environment and the vectors of overconsumption. They thus involve numerous sectors and partnerships (table 5.II).

Table 5.II

Examples of partners and sectors liable to be involved in an ecological and `effort-free' strategic approach.

Objectives and assessment criteria

In contrast to individual approaches, preventive programs targeting the population or community overall do not aim to obtain an improvement in individual body weight or concomitant diseases but to stabilize or reduce the overweight or obesity level and the mean body mass index (BMI) (two closely related parameters) for the target populations as a whole (table 5.III). It should be borne in mind that considerable time may elapse before the environmental and societal changes generate effects with regard to population mean body weight. For that reason, other indicators may be of value as interim efficacy parameters: markers of the degree of physical exercise and choice of foods, but also more structural components such as the number and accessibility of active leisure facilities and the availability and accessibility of fruits and vegetables for low-income populations or in collective institutions, etc. The changes in attitudes and the motivation of the target publics, professionals involved in prevention and public authorities are also important stages and probably indispensable even if they have to be strengthened by subsequent effects on the state of health. Thus, effective preventive and regulatory actions in the field of smoking and road safety would probably not have been possible if they had not been preceded by information, awareness promotion, education and attitude campaigns for the public, rendering the solutions to the problems, including the enforcement measures taken, acceptable.

Table 5.III

Objectives of a large-scale obesity prevention policy.

In addition, great vigilance is necessary in order to prevent and detect adverse collateral effects (Adams and White, 2005): stigmatization, exacerbation of social inequalities, food behavior disorders (Austin, 2001) and nutritional deficiencies, smoking in the hope of preventing weight gain, etc. Such collateral effects are to be incorporated in the assessment criteria.

Assessment, results and evaluation

Generally speaking, the interventions are designed to promote healthy dietary choices and/or an active lifestyle.

Value of a multi-sectorial and concerted plan of action

In line with the ecological model, recent studies have shown that actions combining various strategies (information, awareness promotion and change of attitude, social support and environmental modifications) and several interventional sectors (school but also the family and housing estate) have a greater potential long-term efficacy. Simply encouraging individuals to eat and move differently without modifying their opportunities for food choice and appropriate physical exercise so that they are consistent with the discourse is unlikely to be truly effective.

Community cardiovascular disease prevention programs such as that of North Karelia (Vartiainen et al., 1994; Puska et al., 1998) are, in that respect, exemplary. The programs associated a media campaign targeting the various cardiovascular risk factors (physical exercise, fat intake, smoking, but also hypercholesterolemia and hypertension), educational sessions in the workplace and at school, screening actions for risk factors with individualized counseling, social support and environmental actions (footpath creation, for instance). The programs enabled frequently marked changes in the amount of physical exercise and dietary habits (at least as regard dietary fat intake) and a reduction in cardiovascular morbidity. The effect on weight, which was not included in the objectives, was more inconsistent. It may nonetheless be noted that there was a stabilization in the prevalence of obesity in the North Karelia study compared with an increase in obesity in all neighboring populations. The consistency of such programs was probably an essential prerequisite for their efficacy.

Similarly, an analysis of preventive strategies (IOM, 2002) having shown efficacy for other public health problems such as smoking (CDC, 1999; Yach et al., 2005) or road safety (Gielen and Sleet, 2003) shows the value of the broad interdisciplinary ecological approach taking into account, in a concerted manner, the multifactorial character of behaviors and simultaneously targeting various aspects of the problem, combining information, responsibility promotion and social, environmental and regulatory interventions with a balance between the efforts required of individuals and the structural, environmental and regulatory actions (table 5.IV).

Table 5.IV

12 lessons to be drawn from the anti-smoking campaign (after Yach et al., 2005).

Thus, the results for road safety were obtained because the actions targeted making the infrastructure safe (development of freeways, eradication of black spots, building roundabouts), vehicle safety (active safety: better road holding, regular mechanical control; passive safety: impact absorption and airbags, rigidity of the passenger space), individual responsibility promotion, including through regulations (safety belt wearing mandatory, speed limits, campaign against driving under the influence of alcohol and drugs) and measurements to check that application was effective (monitoring in the field, automatic speed control, for instance).

Nutritional programs and policies proposed and implemented in various countries

It is difficult to summarize the content of all the reports and programs available. It should be stressed that application of the proposed measures appeared from the outset as a long-term task and no concrete result is available for the time being. A few items have nonetheless earned a strong consensus. Among the causes of the obesity epidemic, the generalization of a sedentary lifestyle and the change in eating habits, particularly the adoption of energy-dense foods, strongly promoted by television advertising, have been particularly strongly stressed.

Ultimately, the economic and social cost of obesity is also stressed. Management of obesity and its complications are liable to rapidly exceed the human and financial resources of most healthcare organizations.

The need to act immediately without awaiting definitive scientific proof of the efficacy of the actions that can be implemented is recognized. As a corollary, the need to conduct research and action in parallel and thus to rigorously assess the actions implemented is stressed. The announced or proposed programs are based on the best science available, but nonetheless recognize that it is not always the best science possible. Accordingly, further research on eating behavior and its construction together with the influence of the environment on that behavior appear to be a general need. Furthermore, it is necessary to circulate the results as widely as possible.

The need to act on the environment and not just on the individual is stressed. A failure or weak impact of actions only targeting consumers and consumer education with a view to changing consumer behavior is globally recognized. The concept of an `obesogenic' environment, to be taken in the broader sense (Chopra et al., 2002), involves dietary choices and physical exercise. The promotion of the least valuable foods in nutritional terms through marketing and advertising, particularly television advertising, has been stressed (EHN, 2005). In support of that finding, the important review conducted by the University of Strathclyde demonstrated the influence of television advertising on children's food choices and eating habits (Hastings et al., 2003).

Turning more specifically to childhood obesity, the school occupies a central position in all the proposed policies. This applies to food and nutrition education and also to the food offer in school and the position of physical exercise and sports. Even though the very modest effects of nutritional education demonstrated by the published studies have led EASO not to make health education a priority for coordinated action at European level (EASO, 2002), training children in healthy nutrition is nonetheless cited as an important condition for success (Stockley, 2001; ADA report, 2003). Nutritional education includes education by example and the quality of the meals served in school canteens is an important component (CNA, 1999). This seems to be more easy to implement in Finland, where the state controls school meals, than in the United States, where, despite political resistance related to lobbying (Stilzel, 2003), the problem of competitive pricing for the most nutritionally valid foods remains an important factor to be taken into account (French and Wechsler, 2004). In France, although the nutritional content of the meals served in school canteens was subject to criticism (Czernichow and Martin, 2000), the INCA survey data (data obtained over the period 1998–1999) show that during the period of imposed menus in the primary school children eating regularly in the canteen had a better dietary profile than those who ate no meals or ate rarely in the canteen (Lafay et al., 2002).

The need to promote the awareness, train and involve numerous players such as politicians, health system professionals and school system professionals (ADA Report, 2003; Martin, 2005), economic players (food industry, canteens, communication and leisure) and civil society and parents is stressed. Consistent and concerted action at the various levels (international, national and local) is also stressed.

The nutritional policies proposed in the various reports available are, overall, very similar. Differences are only detected when precise actions are described. Those differences are related to the cultural, political and social contexts of the countries involved. One of the constant features of the programs may be considered a shortcoming: not taking potential collateral effects into consideration. This does not call into question the need to act, but must focus attention on the manner of acting.

Prospects and orientations

In the light of the data and, particularly, the lessons on preventive strategies for other public health problems, it may be considered that a concerted and consistent action at national level targeting the various levels and involving numerous intervention sectors (figure 5.3a, b, c) is advisable in order to implement large-scale effective obesity prevention (IOM, 2005; Swinburn et al., 2005). The need to combine reflection and intervention at the international level also appears essential.

Figure 5.3

Strategy of actions based on the ecological model (after Booth et al., 2001; Davidson and Birch, 2001; IOM, 2005).

National action, as initiated in France with the National Nutrition Health Program ⁴ (PNNS) (HCSP, 2000; table 5.V) must aim for enhanced coordination and consistency of the actions set up by the various partners at local and regional level. The program must promote evaluation of the various actions and their sustainability through support over time. The program must also contribute to setting up regulations and legislative interventions.

Table 5.V

Preventing obesity, limiting the sedentary lifestyle and promoting fruit and vegetable eating are among the objectives of the French National Nutrition Health Program (PNNS).

The politicians and public authorities are strongly involved insofar as implementation of actions requires political commitment that is sustained in duration.

Communities, associations, collective institutions (national, but not only national), schools, local and regional businesses and health agencies are important links in a large-scale prevention policy. In addition to acting as information relays, the foregoing can act directly on the environment to promote opportunities for healthy food choices and an active lifestyle. Numerous potential actions are available, ranging from modification of food offer in schools and the workplace to urbanization and public transport policies.

The food industry, distribution professionals and catering companies are obvious partners for actions addressing food offer. In that field, the efforts of the professionals and public authorities must address the means of rendering the changes legible and acceptable. The changes need to be adopted by the majority of consumers through, among other methods, reflection on nutritional information, advertising and marketing, competitive pricing of the proposed products and regulations.

Similarly, the leisure industry has the opportunity of innovating to promote physical exercise and an active lifestyle as a desirable social standard.

The media and various sources of public information can support the preventive efforts and the regulatory changes or, on the contrary, hamper them.

The familial environment constitutes another sector for decisive intervention. It is frequently more difficult to access. The parents act as a societal model but also intervene through their ability to modulate or control the behavior of their children (encouragement to be active, enrolment in sports, accompaniment if necessary or, conversely, restricting the time the child spends in front of a screen). The consistency of the various sources of information and the setup of environments conducive to health are certainly important stages in promoting evolution of behavior.

The physicians and healthcare professionals are well situated to relay and reinforce the information on food and physical exercise, support the setup of long-term behavioral modifications taking into account the patient's immediate environment, detect changes in body weight early and promote the patient's awareness of those changes. Healthcare professionals also play an awareness promotion role with respect to economic and political decision-makers and the environmental and political changes necessary for an effective preventive strategy. In the face of the challenge constituted by the progression of obesity in our society, which healthcare professionals could not combat alone, innovative modes of operation will probably have to be conceived.

Action at international level appears particularly pertinent for Europe where most of the food legislation and many other legislations relating to the overall environment have already been harmonized. It should be noted, in this context, that the European Union health ministers have proclaimed the ambitious objective of incorporating the nutritional dimension into all national and European public policies (European Union, 2000). In point 12 of the declaration dated December 14, 2000, The Council of the European Union `stressed that numerous community policies, particularly in the fields of public health, agriculture, fisheries, research, transport, consumer protection and the internal market, have such an impact that national nutritional policies can only be fully effective if the aspects relating to nutritional health are taken into account in the definition and implementation of the community policies concerned.'

In conclusion, the obesity epidemic necessitates rapid actions which are to be based on the best available evidence (often a strong presumption of efficacy rather than empirical proof) rather than on the best evidence possible. In the light of the ecological model whose fit has been demonstrated for various public health problems, it would appear essential to develop new approaches that are not only centered on individual information and skills (active changes) but also associated with changes in the social, cultural, political, physical and structural environment which promote physical exercise and the choice of appropriate foods (passive changes). Those approaches cannot be considered the sole responsibility of a given sector but rather call for the active contribution of the public authorities, industrial and business sectors, media, national collective and community collective institutions, school system, consumers, etc. and address numerous action sites (schools, workplaces, housing estates, regions). A critical and rigorous assessment of the actions implemented, taking into account their feasibility, sustainability and the motivation of the players together with their cost-effectiveness and the potential adverse collateral effects is also indispensable.

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Nutrition and obesity prevention: public health priority since 2001

Prevention through nutrition is the subject of a committed public health policy and has been since the launch of the PNNS by the Ministry of Health in January 2001. The program consists of preventive actions and management with objectives to be achieved and a precise schedule. The general objective of the program is to improve the state of health of the French population by acting on one of the major determinants: nutrition. The priority objectives of the PNNS contribute to the combat against obesity (increase in fruit and vegetable consumption, increase in physical exercise, etc.).

Objective No. 8 directly targets reducing the prevalence of overweight and obesity in adults by 20% and halting the increase, particularly large in recent years, in the prevalence of obesity in children.

The French decision may be considered rather late compared to the alarm call issued by WHO during the international conference on nutrition in December 1992 in Rome. Several reasons explain the time lapse.

In a context characterized by the commitment to eradicating `nutritional deficiencies', the weakness of the national alert and health monitoring system, the incomplete nature of the knowledge and the feeling of protection afforded by French cuisine and the `French paradox' contributed to masking the epidemic of obesity. Moreover, nutrition, a poorly implanted and little recognized discipline in the healthcare system, largely exceeds, by the stakes involved, the remit of the Ministry of Health alone. Given that the theme does not elicit an immediate reaction from the French population, the implementation of a preventive policy could raise numerous questions, particularly at ethical and methodological level.

Significant advances

Four years after the launch of the PNNS, the obesity issue, which, outside of the expert circles, attracted little interest in 2001, has become a major preoccupation for society and debates. The legitimacy of a public policy relating to nutrition and obesity is no longer controversial. The PNNS has undoubtedly greatly contributed to that change although the contribution cannot be accurately measured. Since the program's launch, substantial advances have been observed in the deployment of the strategies, programs and actions at both national and local level.

National framework

The national framework took the form of a set of laws, regulations and guidelines together with financing and mobilization operations.

Law, regulations and guidelines

The inter-ministerial permanent steering committee of the PNNS constitutes an essential organization ensuring the launch of actions, management, follow-up and, if necessary, alerting the public authorities. Act No. 2004-806 dated August 9, 2004, relating to public health confirmed the pertinence of the PNNS at legislative level. The objectives of the PNNS were broadly covered by the report appended to the act and defining 100 public health objectives for the period 2004–2008. Objective No. 5 relates to the reduction of the prevalence of adult obesity and includes quantitative measurement of the results (the adult overweight or obese population was to decrease from 42% in 2003 to 33% in 2008). Objective No. 12 maintained the ambition of halting the spread of childhood overweight and obesity.

The consistency of the public policy has been ensured. PNNS 2001–2005 is, de facto, legitimate and has been extended to 2008. The essential imperatives of continuity in the action and duration have been taken into account.

In addition, the public health act is innovative in that it states, for the first time, a limiting framework for certain aspects of food offer: obligation to include health information in the advertising and promotion of soft drinks and manufactured foods (article 29); prohibition of beverage and food product-vending machines accessible to school children from September 1, 2005 (article 30). The foregoing constitutes a considerable advance in the strategy of combating obesity: the plurality of the factors contributing to the epidemic necessitates responses at all levels, including those whose stakes exceed the health field. In April 2005, the submission of bill No. 2191 `Acting against obesity', to Parliament confirmed the awareness of the public health stakes at the highest level.

The period 2001–2004 was characterized by intense regulatory activity with several circulars from the Ministry of Health, for example on food and nutrition in healthcare establishments, the incorporation of the nutrition issue in priority action programs for sensitive populations, the decree dated April 27, 2004, on the conditions for experimental use of the `PNNS' brand or logo. At the Ministry of National Education, several circulars on the issue, which had hitherto been little explored (except the health safety aspects) were circulated during the period. For example, a circular on the composition of meals served in school canteens (2001), and a circular on the morning snack served in schools (2004) were issued. The regulatory activity was based on the work of recognized organizations: recommendations of the French pediatric society (2003), opinion of Afssa (2004), opinion of Anaes (2002), opinion of the CNA (2004), Inserm expert review (2000), resolutions and proposals from the European regulatory authorities, etc.

Budgetary aspects

The PNNS was financed by the National Fund for Health Prevention, Education and Information (FNPEIS, Cnamts) from 2001 through the National Institute for Health Prevention and Education (Inpes) and, from 2002, from provisions of the state budget part of which were delegated to the Regional Health and Social Affairs Organization (Drass). Table 6.I shows an evaluation of the expenditures from 2001 through 2004 by the three institutions for the budget lines `Prevention through nutrition'.

Table 6.I

Expenditures (€ million) on nutritional prevention.

The question of expenditures calls for several remarks: the initial financial commitment by the Ministry of Health was marked compared to other public health programs (except the cancer plan). For the three budgets taken together over the period 2001–2004, the continuous growth in expenditure is clear, particularly in 2004.

The expenditures throughout the country for prevention through nutrition were much greater than those recorded by the budgets of the above three institutions. The financial commitments of other sectors are noteworthy:

• financing actions and personnel expenditures for other ministries and organizations (research, National Education, Inserm, Afssa, Inra, etc.);
• financing by regional collective institutions, which was substantial in some cases. Thus, in 2002, the Drass of the Nord-Pas-de-Calais, region which is highly committed to the issue, estimated that for every Euro spent by the State, the total spending was 4 Euros thanks to the commitment of other local partners;
• several structures set up by the State devote an unidentified share of their credits to prevention through nutrition actions: for example, the cancer plan, the regional health programs, the regional programs for access to prevention and care (Praps), etc.;
• the hospital sector, the liberal professions and the healthcare networks.

Among the various forms of financing for prevention through nutrition, the expenditures specifically targeted on preventing obesity have not been separately identified, if indeed it is possible to do so.

Overall, two findings may nonetheless be formulated:

• despite the State's commitment, which remained constant over the period 2001–2004, there has been an overall increase in expenditures to promote prevention through nutrition;
• public spending has leveraged the financial mobilization of other partners.

Communication, education and information of the general public and healthcare professionals

The national budget credits have, in particular, enabled two types of complementary action to be implemented, one type addressing the population and the other healthcare professionals. All the partners committed to the PNNS have contributed, each in their field of skills.

In addition to the national information campaigns (consumption of fruit and vegetables), several nutrition guides, some general (`Good health through eating: the food guide for all'), others more targeted (parents of children and adolescents, adolescents, physical exercise, etc.), have been drawn up and widely circulated. Each guide is accompanied by a version specifically intended for healthcare professionals. The healthcare professionals and social services sector have also been targeted by instruments adapted to their practices (e.g. a disk enabling calculation of the body mass index, training modules, and a collection of fascicules: `The PNNS reviews'). All the tools developed and circulated were compiled using rigorous methodologies by recognized institutions and scientific experts. This constitutes one of the strengths of the PNNS.

The PNNS website was set up by the Ministry of Health and constitutes a forum for the review of ongoing actions and potential sharing of the experience generated. The Inpes site offers those involved references and practical tools. The National Education site, Eduscol, particularly addresses school canteen professionals.

The increasing demand from elected representatives led to the compilation of tools suitable for municipal players (guide for the use of elected representatives and municipal technicians), specific undertakings (charter: `towns active in the PNNS', in liaison with the association of French mayors), support for inter-communal exchanges, particularly through the French network of health towns (WHO), subsidies for various nutritional projects implemented under the auspices of the municipalities and specific projects deployed by private players in some towns (program: `Together we can prevent childhood obesity', Epode).

In-depth

At national level, numerous think-tanks involving numerous players (economic players, consumers, regional collective institutions, associations, other ministries) have been set up prior to actions that attract little media attention but are as varied as the revision of the nutritional aspects of school books, the setup of the logo, and the mobilization of learned societies, etc. In parallel, Usen has pursued setup of a national epidemiological monitoring system. In addition, the main studies and surveys conducted in France over the last 5 years and collecting data pertinent to nutrition have been inventoried (Usen, InVS, Cnamts, etc.).

Worrying subjects

Despite the methodological reservations reported above, a partial review and assessment of the strategies, programs and actions implemented in France at various levels may now be conducted.

References

1. AFSSA (AGENCE FRANÇAISE DE SECURITE SANITAIRE DES ALIMENTS). Obésité de l'enfant: impact de la publicité télévisée. 7 July 2004.
2. ANAES (AGENCE NATIONALE D'ACCREDITATION ET D'EVALUATION EN SANTE). Prise en charge de l'obésité chez l'enfant et l'adolescent. Recommandations pour la pratique clinique. 2003.
3. CNA (CONSEIL NATIONAL DE L'ALIMENTATION). Avis sur la restauration scolaire révisant les avis antérieurs du CNA. 2004.
4. INSERM (INSTITUT NATIONAL DE LA SANTE ET DE LA RECHERCHE MEDICALE). Obésité, dépistage et prévention chez l'enfant. Éditions Inserm, Paris, 2000.
5. MEN (MINISTERE DE L'EDUCATION NATIONALE). Restauration scolaire. Bulletin officiel spécial N°9 du 28 juin 2001.

The United States' recommendations

In the United States, a remarkable document was published by the North American Association for the Study of Obesity (NAASO) in 1998. The document derived from cooperative work between National Institute of Diabetes and Digestive and Kidney diseases (NIDDK) and the National Heart, Lung, and Blood Institute (NHLBI). The document is entitled `The practical guide: identification, evaluation, and treatment of overweight and obesity in adults⁶.' Based on the evidence-based medicine methodology, the detailed report develops a rational argument for recommendations on the assessment and management of obesity. The recommendations cover several areas and are associated with written and electronic presentations and software.

Recently, updated and simplified recommendations were forwarded to general practitioners by the American College of Physicians (Hegmann, 2005; Snow et al., 2005). The recommendations are based on 5 points: tackling the question with patients consulting their general practitioner and explaining that the objective is not only weight loss but also prevention and treatment of complications; while behavioral measures are the priority, pharmacological treatment is to be envisaged in the event of failure; patients are to be informed of the immediate adverse effects of medications and to be aware that their long-term safety has not been established; surgery is only indicated in the event of morbid obesity and the patient is to be very clearly informed of the risks; candidates for surgery are to be referred to expert centers.

Canadian recommendations

The government of Canada, the Canadian provinces and territories and non-governmental organizations have issued a series of recommendations on obesity (Canadian task force on preventive health care). Outside of the diagnostic recommendations, there is no specific obesity plan like that launched by the NIH in the United States (NIH, 2000) in Canada. However, a series of non-specific measures exists (Douketis et al., 2005). The `integrated' strategy is based on promotion of health and prevention through a healthy diet and physical exercise, which are not only beneficial with regard to obesity but also with regard to the prevention of cancer and cardiovascular disease. The `Canadian food guide for healthy eating' and the `Canadian physical activity guide for a healthy life' have been circulated to help Canadians be physically active and make healthy dietary choices. The strategy targets all Canadians, irrespective of whether they are in good health, at high risk or present with a chronic disease. The 2005 budget provides an envelope of $ 300 million over 5 years.

With a view to preventing infantile obesity, the Canadian government has selected an overall approach to health in schools. Combating obesity thus only constitutes one aspect of public health policy. The Bureau of Nutrition Policy and Promotion supplies teachers with guides and teaching aids. In practice, the recommendations are adapted to each province. In Québec, the government has launched the program entitled `Écoles en forme et en santé'. The program finances school projects designed to give children `healthy life habits, including regular physical exercise and a healthy diet'. Recommendations are given on the composition of packed lunches at school. In low-income areas, `nutrition programs' have been set up subsequent to local initiatives on the part of school communities or non-governmental organizations. These programs, amounting to some € 3 million, are financed by public and private funds (parent associations, companies and businessmen) and implemented by volunteers.

In Ontario, the Ministry of Education has recommended withdrawing excessively fat or sweet products from sale, only selecting foods meeting criteria defined by dietitians and particularly carefully monitoring the size of individual servings. Thus, carbonated soft drinks are to be replaced by pure fruit juices, skimmed milk or bottled water. The document also advises reviewing the contracts concluded with suppliers. In Québec, all commercial advertising targeting children aged less than 13 years is legally prohibited. In the remainder of Canada, advertising targeting children aged less than 12 years is regulated by good conduct codes.

A tax on retail carbonated beverages, fruit juices, fruit drinks, confectionary and snacks (chips, pretzels, popcorn, salted peanuts, crackers, etc.) is applied in most provinces. However, the revenues are not allocated to financing infantile obesity prevention programs.

Recommendations in the European countries

Various recommendations have been published in Europe (Hainer et al., 1998; Swiss Society of Infection Disease, 1999; Dutch Association for the Study of Obesity, 2001; Grandjour et al., 2001; Hancu et al., 2001; Muls 2001; Magnusson, 2005).

European recommendations

The European recommendations on the management of obesity in general practice were compiled by an expert group under the auspices of the European Association for the Study of Obesity (EASO): `Management of obesity in adults: project for European primary care' in 2004⁹. The recommendations define the conditions for first-line diagnosis and management. The conclusions of the report are, practically word for word, the same as the French recommendations of 1998 (Afero et al., 1998; Hainer et al., 2004). Recommendations have been compiled for obesity surgery and for the setup of European reference centers. In addition, EASO has compiled a European training course for physicians wishing to focus on obesity management.

Indian and Chinese recommendations

The two most populous countries in the world, China and India, have also been stricken by the obesity epidemic. Urban and suburban environments are particularly affected. This apparently paradoxical situation in countries that were long affected by malnutrition and under-nutrition in reality reflects fast economic and social change. It is interesting to note that the recommendations have been published in India and China (Bhave et al., 2004; Chen et al., 2004).

Assessment

Assessment of the effective application of the programs and their impact would be premature given their recent nature. Nonetheless, noteworthy differences at the developmental stage may be cited.

Countries like the United States, France and Belgium which have included the recommendations in an overall consistent strategic plan for preventing and treating nutritional diseases or, more specifically, obesity are rare.

Most of the recommendations remain paper documents, articles and guides. The initiatives in the United States and Europe with regard to developing communication tools and training courses with the aim of circulating and promoting application of the recommendations are therefore noteworthy. NAASO has developed a wide range of tools in the service of its recommendations¹⁰. A training program is available to physicians online. Its pedagogic objectives consist in the following fields: pathophysiology of obesity and its complications, relationship between metabolic syndrome, obesity and cardiovascular diseases, obesity treatment. The training courses are available to general practitioners and credited in the in-service training system. EASO has also developed a training program in cooperation with the IOTF. The program, named `Scope', was launched by the Obesity summit of the European Community held in Copenhagen in September 2002. Scope¹¹ validates the training of practitioners trained in obesity.

By generating national and community initiatives worldwide, the impact of the WHO report on obesity was considerable. The report led to the design of recommendations and, in certain cases, action plans for the prevention, diagnosis and treatment of obesity.

The contents of the recommendations do not differ fundamentally from one country to the next. In contrast, important differences in terms of application exist. The differences are both conceptual and practical. Certain countries like Canada have selected a non-specific nutritional prevention option considering that preventing obesity shares the same modalities as preventing cancer and cardiovascular disease. Other countries such as the United States have developed strategic programs specifically targeting obesity. In practical terms, only the United States and the European Community have set up healthcare personnel training strategies with a view to furthering the recommendations. Web tools and online training courses have been developed.

A critical question is that of partnerships. The North American countries have chosen a partnership with industry. That choice has not been explicitly debated in Europe. At the present time, no assessment of the impact of partnership strategies is available.

References

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2. BHAVE S , BAVDEKAR A , OTIV M . IAP NATIONAL TASK FORCE FOR CHILDHOOD. Prevention of Adult Diseases: Childhood Obesity. IAP National Task Force for Childhood Prevention of Adult Diseases: Childhood Obesity Indian Pediatr 2004 41 559 575 . [PubMed: 15235162]
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5. DOUKETIS JD , PARADIS G , KELLER H , MARTINEAU C . Canadian guidelines for body weight classification in adults: application in clinical practice to screen for overweight and obesity and to assess disease risk CMAJ 2005 172 995 998 . [PMC free article: PMC556034] [PubMed: 15824401]
6. DUTCH ASSOCIATION FOR THE STUDY OF OBESITY. Guidelines for general practitioners for the treatment of obesity: A stepwise approach. Recommendations for the diagnosis, the prevention and the treatment of obesity. Amsterdam, 2001.
7. GANDJOUR A , WESTENHÖFER J , WIRTH A , FUCHS CH , LAUTERBACH W . Development process of an evidence-based guideline for the treatment of obesity International Journal for Quality in Health Care 2001 13 325 332 . [PubMed: 11560352]
8. HAINER V , KUNESOVA M , PARIZKOVA J , STICH V , SLABA S . et al. Clinical guidelines for diagnosis and management of obesity in the Czech Republic Sborn Lek 1998 99 235 250 . [PubMed: 10358417]
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14. NATIONAL INSTITUTES OF HEALTH (NIH). National Heart, Lung, and Blood Institute (NHLBI). The practical guide: identification, evaluation, and treatment of overweight and obesity in adults. Bethesda: National Institutes of Health, 2000, NIH publication 00-4084. http://www​.nhlbi.nih​.gov/guidelines/obesity/ob_home.htm.
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16. O'MEARA S, RIEMSMA R, SHIRRAN L, MATHER L, TER RIET G. A systematic review of the clinical effectiveness and cost effectiveness of sibutramine in the management of obesity. Report commissioned by the NHS R&D HTA Programme on behalf of the National Institute for Clinical Excellence. NICE 2000b. http://www​.nice.org.uk​/pdf/sibutraminehtareport.pdf.
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18. ROYAL COLLEGE OF PHYSICIANS. Report of the Nutrition Committee of the Royal College of Physicians of London. Anti-obesity drugs: guidance on appropriate prescribing and management. RCP, London 2003.
19. SIGN (SCOTTISH INTERCOLLEGIATE GUIDELINES NETWORK). Obesity in Scotland. Integrating prevention with weight management. A national clinical guideline recommended for use in, Edinburgh, 1996.
20. SNOW V , BARRY P , FITTERMAN N , QASEEM A , WEISS K . Clinical Efficacy Assessment Subcommittee of the American College of Physicians. Pharmacologic and surgical management of obesity in primary care: a clinical practice guideline from the American College of Physicians. Ann Intern Med 2005, 142: 525–531. Summaries for patients. Treating obesity with drugs and surgery: a clinical practice guideline from the American College of Physicians Ann Intern Med 2005 142 I55 . [PubMed: 15809464]
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National, regional or local strategies

Several strategies have been developed at national level to modify eating habits and lifestyle, to train physicians and promote their awareness with regard to the early screening for and treatment of childhood obesity, and to develop professional networks. Actions set up at regional or local level also constitute examples.

Setup of pediatric obesity prevention, screening and management networks: the Répop

The model of an open-care-hospital network for childhood obesity was finalized by a Dhos working group in the context of devolving the PNNS to healthcare establishments (figure 8.1). In the 2002 call for projects, 3 pilot sites were selected: Paris/Ile-de-France, Toulouse and Lyon. The first two have been active since September 2003 and will be evaluated after 2 years of operation. The `Grand Lyon' Répop began later, at the same time as another network in Franche-Comté. Apop has greatly promoted the exchange of information and tools, providing the impetus for project compilation and regional financing from the regional hospitalization agencies (ARH), regional health insurance unions (Urcam) and regional network management (DRR). A recently finalized guide is available from the PNNS website. Other Répop have also now made considerable progress.

Figure 8.1

Répop model proposed in 2002 by the Dhos working group. * Healthcare homes for children

Screening for childhood obesity

As is the case in most countries, France has no organized, systematic national program to screen for childhood obesity. This in part explains the delayed diagnosis and management of the disease.

How to screen?

Obesity screening cannot be conducted by simply inspecting the child or weighing him/her. It is necessary to calculate the BMI [BMI = weight (kg)/height² (m)] and the corpulence curve is to be plotted in the child's health diary at each visit by the physician. The cutoffs defining overweight and obesity must be known (table 8.I).

Table 8.I

Terms and cutoffs used to define overweight and obesity.

Management of obese children

Few studies of the management of obese young children (age less than 6 years) have been published, probably due to the frequent delay in diagnosis. In contrast, studies of obesity management programs for children aged over 7 years have been conducted in North America and Europe. Numerous studies are available.

References

1. ANAES. Recommandations pour la prise en charge de l'obésité de l'enfant et de l'adolescent. 2003.
2. BARLOW SE, DIETZ WH. Obesity evaluation and treatment: expert committee recommendations. Pediatrics 1998, 102: E29 (web only, http://www​.pediatrics​.org/cgi/content/full/102/3/e29) [PubMed: 9724677]
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4. CHAMBERLIN LA , SHERMAN SN , JAIN A , POWERS SW , WHITAKER RC . The challenge of preventing and treating obesity in low-income, preschool children Arch Pediatr Adolesc Med 2002 156 662 668 . [PubMed: 12090832]
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Data sources and conceptual bases

The data available for the analysis of the problems raised by adolescent obesity are of three orders:

• knowledge of the behavior of adolescents in general and their lifestyle, studies comparing obese groups with normal-weight groups without interventional studies;
• the results of interventional studies on adolescents in various countries;
• the very heterogeneous national programs and recommendations; the heterogeneity resides in the formulation which derives from the above observations and takes each of the components into account to a variable degree.

Screening and public health actions

In 2000, the Inserm collective expert review constituted an initial assessment of screening and obesity prevention in children and confirmed the need for early, prolonged and multidisciplinary actions (Inserm, 2000).

In 2002, the International Obesity Task Force (IOTF) chaired by Prof. Philip James, published an initial report calling for decisive action worldwide in the interest of children and adolescents (Obesity in Europe, the case for action). In 2004, a worldwide review of the situation of children and adolescents stressed the multiple shared features of the obesity epidemic worldwide and, thus, the double constraint of multidisciplinary actions that are adapted to local situations. A breakthrough in the scientific bases for the combat against obesity thus occurred less than 10 years ago.

In France, the National Nutrition Health Program (PNNS) launched a few weeks after the presentation of the Inserm expert review defined as its major objective the stabilization of childhood and adolescence obesity prevalence. The tools developed for the program (curves, rules, software, etc.) cover all age groups and, in principle, target all general practitioners and pediatricians. The PNNS stressed the particular importance of a consistent strategy addressing young people: consistency between the information, education and food offer.

The document entitled 'I like to eat, I like to move, nutritional guide for adolescents' intended for adolescents was published in the third quarter, 2004. As the General inspectorate of social affairs (Igas) stressed in 2003 in its report entitled 'Prevention through good nutritional hygiene', we can only regret the lack of financial and human resources allocated to implementing that mission. The situation led to the nutritional information objectives for children only being achieved over a timeframe of more than 3 years.

The Anaes recommendations on the 'Management of obesity in children and adolescents' published in 2003 are rather academic and not very pragmatic. Since then, the Association for the Management of Pediatric Obesity (Apop), with the approval of the pediatric societies, has developed a practical formation module consisting of two sub-modules, children and adolescents. The modules are intended for physicians. The adolescent sub-module develops an approach integrating the difficulties specific to adolescents, in particular the psychological background and the risk of food behavior disorders.

The strengths and weaknesses of the program in France need to be seen in perspective: only in 2005 did the British medical association, Swedish National food administration and US National institute of health published their reports and recommendations. In contrast, Scotland published its own practical recommendations for management and screening in 2003: the document consisted in a 'Quick reference guide' that could be downloaded¹⁴. The preventive programs have frequently developed instruments whose use is restricted to the operations provided for in the programs. The circulation and exchange of instruments would enable substantial time and money savings in other regions.

Curative treatments

The treatment of adolescent obesity is beset with several specific difficulties: the absence of effective medication having received regulatory approval for the age group, the risk of inducing or exacerbating an emergent eating behavior disorder, and the danger of adverse effects of serotonin reuptake inhibitors, which are effective on food cravings but would appear more hazardous for adolescents.

In addition, obesity, particularly when it is severe, gives rise to peer stigmatization necessitating accentuation of the social and psychological management. Adolescence is now a period of very severe obesity onset whose complications have clinical repercussions and require appropriate management (Frelut, 2001).

References

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10. DAO HH , FRELUT ML , PERES G , BOURGEOIS P , NAVARRO J . Effects of a multidisciplinary weight loss intervention on anaerobic and aerobic aptitudes in severely obese adolescents Int J Obes Relat Metab Disord 2004 28 870 878 . [PubMed: 15170464]
11. DAO HH , FRELUT ML , OBERLIN F , PERES G , BOURGEOIS P , NAVARRO J . Effects of a multidisciplinary weight loss intervention on body composition in obese adolescents Int J Obes Relat Metab Disord 2004 28 290 299 . [PubMed: 14970838]
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22. IOTF. Obesity in Europe, 3 International Obesity Task Force, March 2005. www​.iotf.org.
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Data sources and conceptual bases

For the last 10 years, expert groups have met under the auspices of the International Obesity Task Force (IOTF) to propose a consensus and good clinical practices (SIGN, 1996; NIH, 1998; WHO, 1998; WHO, 2003; EASO, 2004). An immense amount of work on a synthesis has thus been implemented. The recommendations issued by the expert groups have been validated for France by Anaes (Alfediam et al., 1998). Numerous meta-analyses and reports have also been published (McTigue et al., 2003; Avenell et al., 2004a; Li et al., 2005).

Primary objectives

WHO indicates (WHO, 1998) that obesity management has four objectives of increasing importance: weight loss, treatment of concomitant diseases, weight stabilization and prevention of weight gain.

Weight loss of 5 to 15% vs. baseline is both realistic and sufficient (SIGN, 1996; NIH, 1998; WHO, 1998; table 10.I). However, greater weight loss may be advisable in cases of massive obesity or when the seriousness of the concomitant diseases necessitates a greater weight loss. Halting weight gain is already a valuable objective for failures or people who are only a little overweight.

Table 10.I

Theoretical benefits of weight loss of 10 kg (after SIGN, 1996).

Preventing relapse is of capital importance. Weight regain after weight loss is the natural course. This is difficult for patients and physicians to accept. There are in fact numerous resistance factors with regard to weight loss. Those factors are physiological, genetic, related to environmental pressure, psychological and behavioral.

The management of concomitant diseases is one of the priority objectives. The control of diabetes, hypertension and other vascular risk factors, the alleviation of osteoarthritic pain and the treatment of sleep apnea syndrome (SAS) should not be neglected to the advantage of weight loss alone. Weight loss is not always sufficient in itself (Ziegler and Quilliot, 2005).

A last objective is the patient's quality of life in its three dimensions: somatic, psychological and social. Enhancing well-being, self-esteem and social integration do not necessarily require massive weight loss.

Personalized strategy based on the risk associated with obesity

Two anthropometric parameters are used to evaluate the risk related to excess adiposity: body mass index (BMI) and waist measurement (tables 10.II and 10.III). BMI is closely correlated with fat mass while waist measurement is a more simple index enabling evaluation of the central or android character of the obesity, which is associated with an increase in the risk of cardiovascular disease, type 2 diabetes mellitus and certain forms of cancer. Concomitant diseases obviously constitute an additional argument for effective management.

Table 10.II

Definitions of obesity and overweight in adults as per the International Obesity Task Force (after WHO, 1998).

Table 10.III

Waist measurement cutoffs associated with a risk of concomitant diseases (cardiovascular disease, type 2 diabetes mellitus, dyslipidemia, certain forms of cancer) (after ALFEDIAM, 1998; WHO, 1998; IDF, 2005).

Early intervention is recommended. Obesity is a chronic, serious and recurrent disease. It is logical to detect people and situations at risk in order to act the most effectively and as early as possible.

Therapeutic resources

There are a number of therapeutic resources: dietetic treatment, promotion of physical exercise, psychological and behavioral management, medication and surgery.

Nutritional counseling

The choice of therapy is a two-stage process. The magnitude of the energy deficit conditions the magnitude of the weight loss, irrespective of whether the calorie restrictions target lipids, carbohydrates or protein. The qualitative choice, i.e. the 'type of diet', considerably influences the initial acceptance and long-term compliance, which are obviously decisive.

Quantitative aspects

Broadly speaking, three categories of diet may be distinguished on the basis of the calorie deficit proposed (Basdevant et al., 1998; WHO, 1998; WHO, 2003).

Little-restrictive personalized diets are preferred in the good clinical practice recommendations. The diet is prescribed for a few months (3 to 6 months). The energy deficit is 300–600 kcal/d, i.e. 15 to 30% of the energy requirements, and leads to a loss of 1 to 2 kg per month.

Low-calorie diets (LCD) procure 800 to 1200–1500 kcal/d. They thus impose a considerable reduction in energy intake, which may exceed 50% relative to the subject's requirements. Compliance over the long term is difficult. LCD are also associated with a risk of multiple nutritional deficiencies. In consequence, the duration is not to exceed a few weeks.

Very low-calorie diet (VLCD) (≤800 kcal/d) are only to be used under strict medical supervision for periods not exceeding 4 weeks (Basdevant et al., 1998; WHO, 1998; WHO, 2003). VLCD are very effective causing average weight loss of 4 to 8 kg per month or even more. The principal risk is weight rebound in the weeks following the end of treatment. The loss of lean mass, which is almost inevitable, seems to be more marked the less the patient is obese. The serious complications (hypokaliemia, dehydration, arrhythmia, malnutrition, etc.) are rare when the diets are correctly implemented in compliance with the conditions, particularly the contra-indications, such as, for instance, heart disease, type 1 diabetes mellitus, advanced age or progressive disease.

Qualitative aspects

Dietary macronutrient intakes are expressed as a percentage of the total energy intake (TEI). In most diets, 45 to 65% of the TEI is derived from carbohydrates (C), 20 to 35% from lipids (L) and 10 to 35% from protein (P). Maintaining the nitrogen balance is indispensable for preservation of lean mass. The minimum daily intake is 70 g for men and 60 g for women. The proteins are to be of good quality and contain the essential amino acids (Ziegler et al., 1997). The more severe the diet, the more the proportion of protein (P %) increases. Balanced diets which are moderately low-calorie diets have the following C-L-P breakdown: 50–35–15% of the TEI. The tactical choice bears on the proportion of carbohydrates and lipids (Ziegler et al., 2005).

Low-fat diets are diets in which fat food consumption is restricted and a proportion of the missing calories is replaced by high carbohydrate or protein foods. Lipid intakes range from 30 to less than 15% of the TEI (C-L-P: 55–30–15 to 70–15–15% of the TEI).

In high-protein diets, the protein-rich foods are preferred to carbohydrate-rich foods (C-L-P: for example 40–30–30% of the TEI) and/or lipid intake (C-L-P: for example 45–25–30%). In practice, it is difficult to promote protein intake without increasing the lipid ration.

Protein diets are a variant of the VLCD which use dietary preparations (liquid or solid) that have a very low lipid and carbohydrate content and whose micronutrient content is regulated. Protein-sparing modified fast (PSMF) diets consist in foods that are naturally rich in good-quality protein and particularly low in fats (chicken breast, egg white, ham, cottage cheese). Potassium (2–3 g/d) and vitamin supplementation is then necessary.

Low-carbohydrate diets are currently encountering a degree of success since they appear simple and easy to follow. Dieters are advised to avoid consuming foods with a high carbohydrate content (bread, starchy foods, legumes, confectionery). Diets with a moderately low carbohydrate content (low-carb diet) supply less than 45% of the calories in the form of carbohydrates. The C-L-P distribution is thus close to 40–30–30%. Very low-carb diets restrict carbohydrates to less than 50–100 g/d, i.e. less than 10% of the TEI. The reduction (< 50 g/d) is drastic in ketogenic diets. Dietary carbohydrates may be replaced by foods with a high protein or lipid content whose consumption is not restricted (C-L-P: 15–55–30%). Several studies have shown that the latter diets induce enhanced control of hypertriglyceridemia and low HDL cholesterol levels than the usual low-fat approach. However, those diets are difficult to observe over a long period, considerably reducing their value.

It should be noted that the various 'high this or low that' diets have not demonstrated their value. Their promotion is not devoid of financial interest. Even the concept of diets is open to debate. Personalized nutritional counseling (table 10.IV) is widely used in France in the context of programs including various measures.

Table 10.IV

Nutritional advice (after Basdevant et al., 1998; Gougis et al., 2004; Ziegler et al., 2005).

Results and evaluation

The efficacy of obesity treatments would seem easy to evaluate and numerous literature reviews have addressed the subject. However, that is not the case for many reasons, mainly methodological. The protocols are rarely comparable. For instance, the grouping of studies of differing durations in certain meta-analyses seems debatable. Moreover, long-term studies are rare and few involve determinations addressing dietetics, physical exercise and counseling to modify general behavior (McTigue et al., 2003). Only the positive studies are published. The debate is thus not always free from bias.

Older studies showed that only 5% of patients were able to lose weight and maintain the loss for 5 years. However, that pessimistic conclusion has been challenged by recent studies (McTigue et al., 2003; Avenell et al., 2004; Li et al., 2005). Moreover, even if the results in terms of body weight are modest, they may be sufficient to have positive effects on quality of life and concomitant diseases (NIH, 1998; WHO, 1998; Tuomilehto et al., 2001; DPP, 2002).

Prospects and orientations

In the field of obesity, medicine has markedly evolved over the last 20 years. The strengths are worthy of note. A French culture is developing as shown by the publication of the first medical treatise on obesity in 2005 (Basdevant and Guy-Grand, 2004). French specialists have contributed to the international consensuses. Recommendations were proposed in 1998 and subsequently validated by the Anaes. Bariatric surgery has also attracted considerable interest. The PNNS has clearly described the major options in the field of promoting health. There is thus a degree of national consistency, which now needs to be put into practice.

However, a number of weaknesses also deserve attention. The training given to physicians and paramedical personnel could be improved since obesity is a complex disease and poorly understood. Treatment failures often result from tactical errors: unrealistic objectives, excessively severe diets, absence of response to the patient's expectations and not taking the patient's motivation into account.

It would appear necessary not only to increase the care offer but also to organize the healthcare system better to promote enhanced access while promoting development of the new skills indispensable for control of the epidemic.

Increasing the care offer

The French care system seems little adapted to the management of the obesity epidemic that is occurring, even though the system is evolving (Basdevant et al., 2004; Ziegler et al., 2005).

Medical offer

The attending physician is naturally the pivot of the system (table 10.V, Ziegler et al., 2004). Since the attending physician knows the patient and his/her family, he/she is generally the best placed to ensure the coordination of screening and care. But that requires a personal involvement and time, new resources and recognition of a preventive and educational action.

Table 10.V

Organization of the healthcare system to deal with the obesity epidemic (after (Ziegler et al., 2004).

The second line of defense involves physicians with experience in obesity medicine (physicians qualified in nutrition, endocrine disease and diabetes specialists, internal medicine specialists) or organ specialists. Serious eating behavior disorders, severe or very early obesity, complicated obesity (sleep apnea syndrome, diabetes, respiratory insufficiency, heart failure, etc.) require specialists.

Other healthcare professionals

The conventional role allocated to dietitians, whose importance is recognized by all the expert consensuses, is clearly inadequate in France (Krempf, 2003). The healthcare system ignores dietitians at the hospital and in open-care. Their practices are not included in the official nomenclature and not reimbursed for patients who consult in open-care.

Psychologists could also play an important role. Cognitive and behavioral approaches are rarely used since there are no positions in the hospital environment and setup is difficult in open-care.

The promotion of physical exercise and the combat against sedentariness are essential. Physiotherapists could be called on more to get sedentary people moving, as a function of their handicap, their functional capabilities and the risk factors. Physical education teachers and trainers could also contribute to the actions of prevention and promotion of health through physical exercise. New professions are to be created in that field.

Open-care and hospital nurses are currently little or not at all involved. They could nonetheless fulfill a great number of functions in the long-term follow-up of patients, as is the case in certain countries such as the United Kingdom.

Pharmacists are well placed to promote the attention of the overall population and that of subjects at risk with respect to nutritional diseases. Pharmacists constitute an information relay with regard to both care and prevention that is not sufficiently exploited.

Midwives could be more involved in the prevention of excessive weight gain during pregnancy and in the control of a balanced diet given the antenatal programming of metabolic diseases.

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US initiative: `Strategic plan for NIH obesity research'

For the NIH¹⁶, obesity research has become a priority. The first condition was to combine basic research, clinical research and population-based research with the objective of transferring knowledge for the benefit of individual and collective interventions. The aim was to elucidate and respond to a particularly complex public health issue. Only an interdisciplinary approach enables elucidation of a system resulting from the complex interactions of behavioral, environmental, socioeconomic and cultural factors and revealing predisposing biological factors, particularly underlying genetic factors. The combat against the spread of obesity thus called for a national collective effort, involving not only the NIH but also other government agencies and other players (academics, politicians, economists and associations). The NIH plan of action, while essential, is thus only a component of a national effort.

Objectives and subjects

Four main subjects were selected for the strategic plan.

Prevention and treatment of obesity by modifying lifestyles

The definition of preventive and therapeutic strategies involves identification of the behavioral and environmental factors contributing to the development of obesity in children and adults, the design and assessment of interventional strategies, study of the effects of specific modifications of diet and physical exercise, and the role of the environment inducing excessive calorie intake and sedentariness. It is also important to study how the recommendations are perceived and applied by healthcare professionals and individuals. The plan encourages the study of conceptual models of change in behavior and the study of factors influencing beliefs, perceptions, attitudes and motivations. The work is also to address different populations at various ages and to address the genetic factors determining individual susceptibilities. The latter not only involve energy expenditures but also other dietary behaviors.

Short-, medium- and long-term objectives were defined for the various studies (table 11.I).

Table 11.I

Objectives of the short-, medium- and long-term studies.

The plan of action gave rise to a series of subsidies to ongoing studies on: the effects of changes in macronutrient composition on food intake and body composition; the molecular and behavioral mechanisms involved in weight gain after weight loss; interventions in school and occupational settings; prospective follow-up of a cohort of 100,000 children over 21 years; impulsive and addictive eating behaviors; the relationships between obesity and cancer; the effects of modifying the environment (architecture, urbanization policy, transport system, etc.). Support has also been given to studies of economic factors.

Prevention and treatment of obesity by pharmacological, surgical and other approaches

Control of food intake is a complex process involving a biopsychological system in which multiple internal and external determinants intervene. A neurohormonal set acts as the medium for transmission of information on digestive, absorptive and post-absorptive status, the level of energy reserves and, more generally, nutritional status. Homeostatic, metabolic, hormonal and nervous signals are sent from the peripheral tissues to all of the body, in particular the brain. The central nervous system is responsible for integrating the messages from the periphery and triggering the appropriate adaptational responses, which do not simply consist in the immediate metabolic aspects but also take into account learning, conditioning and memory, together with sensory and affective factors. On that neurohormonal system are superimposed psychological and social factors soliciting memory, pleasure and many other functions. The two-level integration results in food intake fitting individual requirements. The start and end of the meal result from the balance between the stimulatory and inhibitory factors. The triggers for food intake are external (sensory perceptions) and internal (energy reserve status). The inhibitors are digestive and postingestive, triggering the suppression of hunger, then fullness, then satiety. The relative contributions of the many factors triggering food intake are under debate. The contributions vary from one individual to the next and depending on the situation. Elucidation of the biological bases of energetic homeostasis by means of molecular and genetic studies should enable definition and evaluation of pharmacological and surgical treatments. The approach above all targets treatment, but in certain clearly identified circumstances of weight gain (e.g. weight gain on neuroleptics, after brain surgery or after quitting smoking) pharmacological preventive strategies may be envisaged.

The forms of genetic obesity in animals and man constitute models enabling identification of the role of certain molecules or neurohormonal systems and also constitute a series of experimental models. Once again, there is an imperious need to develop models enabling analysis of gene-environmental interactions. The underlying hypothesis, which has yet to be proven, is that preventive strategies are to be oriented as a function of genetic status.

In the field of prevention, short- and medium-term objectives consist in identifying the genes predisposing to behavioral and environmental factor effects in various well characterized populations. In the longer term, the objective is to analyze the factors resulting in weight regain after dieting in order to develop strategies to prevent body weight rebound. Another major objective is to elucidate the biological, behavioral and environmental factors which induce weight gain during critical periods for body weight status during life: fetal and neonatal period, adolescence, pregnancy and menopause. Once again, targeted prevention strategies would appear feasible. Those strategies would be based on behavioral and/or pharmacological actions targeting subjects known to be predisposed on the basis of the studies cited above.

With that aim, the NIH provides support to programs in the following fields: integrative approach to energy homeostasis, obesity genetics and genomics, intrauterine and neonatal factors, role of antipsychotic drugs.

Links between obesity and its complications

Elucidation of the pathophysiology of the various complications of obesity (particularly type 2 diabetes mellitus, cardiovascular diseases, hepatic steatosis, cancer and osteoarthritis) necessitates, among other things, study of the molecules secreted by adipocytes and responsible for inflammation, hypertension and insulin-resistance, and study of the cellular and biological characteristics of the various adipocyte deposits. The prevention of complications should be based on the identification of molecular biomarkers, molecular signatures enabling elucidation of the risk or initial stage of complications in various populations. From that point on, preventive strategies targeting the complications could be envisaged.

In the short and intermediate terms, the objectives of the research program in that field are: defining methods for data collection in order to develop epidemiological studies enabling identification and evaluation of the various complications in various populations; identifying new biomarkers using genomic and proteomic approaches; elucidating the relationships between obesity, inflammation and the development of complications; and determining the predictive value of the biomarkers. In the longer term, the objective is to determine the variations in genetic susceptibility in order to optimize preventive and therapeutic strategies and test new preventive strategies.

The NIH strategic plan is providing particular support to studies applying proteomic methods to the identification of biomarkers, studies of adipose tissue heterogeneity and transdisciplinary studies on energy metabolism and cancer.

Other subjects

The NIH strategic plan includes a series of other measures of a different nature. The question of social inequalities is central. In the United States, the social disparities in health are particularly marked, amplifying what is also observed in Europe. The objective is to differentiate the public health actions and messages. The program, in all those facets, insists on the priority targets, i.e. the populations particularly affected by obesity for ethnic and socioeconomic reasons, the elderly or handicapped and extremely obese subjects. The strategic plan incites development of new methodologies for investigation of eating behavior, energy expenditure and body composition and the development of investigator training. Setup of multi- and interdisciplinary research teams is strongly encouraged. The strategic plan recommends developing an interdisciplinary approach by combining the study of behavioral and environmental determinants in a culturally sensitive manner with the study of biological and genetic factors. It is thus recommended that the interdisciplinary research structures include clinical investigators experienced in phenotyping obesity and in metabolic and endocrine investigation, psychobiology specialists, experts in functional imaging and biology researchers. Similarly, it is considered important to develop translational research moving from basic research toward clinical research and from clinical trials toward population-based interventions. Thus, the need for research on the modalities of transferring knowledge and information to healthcare professionals and the public is stressed. The NIH has also launched partnerships with other governmental agencies, professional organizations and private organizations in order to tackle the questions and their strong implications for society.

The short-term objectives are: to identify the methodological obstacle restricting research progress (e.g. instruments to asses the energy balance); to increase the efforts to create truly interdisciplinary structures; and to identify research and transfer networks. In the medium term, the objectives are: to develop information collection technologies enabling evaluation of behavior and environmental exposure; and to test the utility of the new markers in the evaluation of the impact of preventive and therapeutic measures. The objective is also to evaluate medical practices with respect to nutritional and physical exercise counseling and to identify the obstacles to transmission and implementation of recommendations. Particular attention is to be paid to evaluating the impact of public health campaigns and to the scope for preventive partnerships with political, economic and social players. The question of preventive behavioral counseling has also been tackled, together with that of delegating skills. Research is also investigating the modalities and impact of information for the public, decision-makers and public organizations.

Report of the Institute of Medicine of the National Academies

In 2001, the US Surgeon General published a `Call to action to prevent and decrease overweight and obesity'. At the request of the US Congress, the Centers for Disease Control and prevention (CDC) asked the Institute of Medicine to develop a plan of action for the prevention of obesity. The action mobilized 19 multidisciplinary committees. The full report is available online¹⁷. Although the investment in the research was USD 379 million at the NIH, the Academies have pleaded for further investment. Three priority subjects have been selected: assessment of prevention programs, research on behavior and research on community actions (economic, environmental). A table of priority actions has been compiled and states the players (table 11.II).

Table 11.II

Priority actions (after the report by the Institute of Medicine of the National Academies).

The report insists on cost-effectiveness evaluation of the studies. Effectiveness cannot be separated from profitability. The CDC are currently working on the Move project which is calculating the cost-effectiveness of an intervention targeting physical exercise. The following assessment of the studies ongoing and expenditures committed in the United States has been reported: Food stamp program USD 20 billion; WIC USD 4.3 billion; National school lunch program USD 6.9 billion; School breakfast program USD 1.6 billion; Child and adult care food program USD 1.9 billion.

Canadian initiative

In Canada¹⁸, a large share of the national research on obesity is financed by the Institute of Nutrition, Metabolism and Diabetes (INMD), one of the 13 institutes of the Canadian Institutes of Health Research (CIHR). In 2001, the INMD launched a strategic initiative entitled `Excellence, innovation and progress in the study of obesity and healthy body weight'. The INMD is looking to attract scientists working in various disciplines to obesity research. The INMD supports projects on the complications of obesity, on indigenous people communities and preventive actions and programs on health promotion. The `Canada in movement' program, a preventive program financed by the INMD and its partners, encourages adult Canadians to evaluate their physical exercise using pedometers and to upload the data on their personal activities to an online research instrument.

The program supports various partnerships such as the Canadian Heart Disease Foundation, the Canadian Diabetes Association, the Canadian Kidney Foundation, Canada Health and several other institutes of the CIHR, including the Cancer Institute, the Institute of Women's and Men's Health, the Institute of the Musculoskeletal System and Osteoarthritis, the Institute of Circulatory and Respiratory Health, the Institute of Aboriginal Peoples' Health and the Institute of Human Development, Child and Youth Health. In Canada, the subject of obesity is a priority for the CIHR, the main subsidizing organization. In 1999–2000, $ 4.2 million were invested in obesity research. In 2004, the subsidies increased three-fold to $ 15 million.

European Community

In January 2003, under the auspices of the European Community, experts met at the Rowett Research Institute in Aberdeen to analyze the conditions under which European research on obesity could progress¹⁹. The initial recommendations were as follows: promoting pathophysiological studies incorporating human and animal genetics; setting up interventional studies on management and the effects of early nutrition.

It was suggested that the programs should be conducted in the context of a European institute for obesity research, a virtual institute, or an excellence network in the context of the 6th framework program for technological research and development (FPTRD). The objective was to harmonize the methodologies, manage common resources, coordinate training and increase the visibility of the research. Subsequent to the initial meeting, various initiatives were taken to advance the definition of the subjects and projects under the guidance of Wim Saris (The Netherlands), Arne Astrup (Denmark), Jon Arch (United Kingdom), Bert Koletzko (Germany) and Dominique Langin (France). Considering the stakes for society, the experts insisted from the outset on a series of proposals to be taken into account when considering the political choices for public health and research (table 11.III).

Table 11.III

Proposals of the European Community expert group.

The questions facing the care system and which must be elucidated by research consist in the origins of the obesity epidemic and the definition of realistic preventive strategies, effective therapeutic strategies, and an integrative approach. In this context, it seems essential to improve the definition of the natural history of the disease, inter-individual variations in susceptibility and the reasons for treatment failures. Progress depends on enhanced elucidation of the molecular and cellular mechanisms underlying the development and chronicity of the disease as a function of the behavioral, psychological and environmental determinants. Special attention is to be paid to perinatal determinants. The ambition is to decrease the prevalence of adult obesity and reduce the current progression of childhood prevalence. This calls for enhanced understanding of the early determinants of the disease.

In order to respond to that situation, the experts recommended developing research and training excellence networks that can incorporate animal and human studies, and run studies at the molecular, clinical and population levels, in the context of multidisciplinary teams drawing on clinical centers and research centers including specialists in behavior, economics and social sciences. The structures are to promote the setup of shared methodologies and standardized procedures and enable implementation of large-scale quality studies using appropriate infrastructures. The research teams are to have access to biological resources (DNA and tissue banks).

The immediate issues may be divided into 3 categories:

• genetics and biotechnology: characterizing the genetic bases (gene expression and proteomics), biomarkers, gene-environment-physiology interactions, genetic susceptibility factors for obesity and its complications, pharmacological targets, genetic studies;
• lifestyle modification: multicenter, randomized studies on weight loss strategies including study of predictive factors (biological, genetic, behavioral) and definition of assessment and validation criteria;
• early nutrition: in this field, the key questions are: the effects of perinatal early nutrition on the risk of obesity; determining the critical periods and analyzing the program mechanisms; the respective effects of the environment and genetics on the development of obesity in children; the impact of nutritional information, dietary habits, sensory factors and physical exercise on obesity; the determinants of adiposity rebound in children; the development of obesity complications in children; the epidemiology of obesity in Europe and the regional differences.

The technologies to be developed in order to implement the scientific projects are: genomics, proteomics, bioinformatics, molecular imaging and all the genetic approaches. Considerable clinical resources are also required. This supposes the setting up of competitive, high-performance clinical research centers and sharing databanks. One technical problem to be resolved consists in the miniaturization of tissue specimens, particularly adipose and muscle tissue specimens. Lastly, food and nutritional phenotyping (energy balance, body composition) remains a difficulty for large-scale studies. Cooperation with the specialists in food behavior, sociologists and economists will undoubtedly be essential. Expertise in the human and social sciences is an essential element of the interdisciplinary approach to the field of obesity.

The ethnic, cultural and social heterogeneity of the European population is considered a considerable strength for obesity research in Europe. The heterogeneity gives rise to marked differences in forms of eating habits and, more generally, lifestyle, which add their effects to those of the genetic variables.

In order to implement the European obesity research policy, the constitution of a virtual institute has been proposed. The institute would act as a coordinating center for the research, build and administer a biobank, define quality criteria, constitute a source of information on European obesity research, constitute an interface for political decision-makers, and promote debate between associations, consumers and industry. The institute would standardize the investigation procedures, monitor study quality, monitor resource optimization, monitor databank management and monitor the setup of interdisciplinary research platforms. It is essential to ensure investigator training and mobility. A similar approach was developed in the content of the Nugenob project.

European programs

A few ongoing or pending European projects are cited below as examples.

Research in the National Nutrition Health Program (PNNS)

France made nutrition one of its priorities during its presidency of the European Union. A resolution on the subject was adopted when the Council of European Ministers met on December 14, 2000. In 1999, The Directorate General for Health (DGS) requested the opinion of the various national experts. Launched in January 2001, the National Nutrition Health Program (PNNS) is coordinated by the Secretariat of State for Health and the Handicapped in liaison with the National Education, Agriculture, Research, Youth and Sports and Consumer Affairs. The major orientations, based on the work of the High Committee for Public Health, the National Council for Food and the technical managements of the various ministries involved, in liaison with the Assembly of French Departments, the French Agency for the Safety of Health Products, the Institute for Health Monitoring, the National Insurance Organization, the National Federation of French Mutual Insurance Organizations, scientific leaders and consumer representatives, have been defined. The PNNS associates all the public and private players involved in the fields of intervention defined: research, training and monitoring, actions in the field, promotion, prevention and care, food offer, distribution and control. The main objective of the PNNS is to improve the state of health of the population as a whole by acting on one of the major determinants, namely nutrition. The PNNS has stated that only research-based data enable a scientific basis, the wish of all the players, for orienting the objectives and strategy of nutritional policy. The research is one of the six strategic avenues: 'developing human nutrition research: epidemiological, behavioral and clinical research'. The objective is to develop nutrition research oriented toward public health, particularly through inter-institutional networking. The PNNS first recommended setting up the European reference diet network (Rare) under the auspices of the Ministry of Research. The technological research network's objective was to develop large-scale research actions associating public research with agricultural socioeconomic partners, the food industry, the distribution industry and consumer representatives. Organized in consortia or complementary scientific program groups, the network is to have different components covering the fields of microbiological safety, food science and human nutrition. The latter, the Nutrialis action, was oriented toward the study of eating behavior and the prevention of major diseases (cancer, obesity, cardiovascular diseases) by nutrition. Secondarily, the network recommended promoting the development of public health nutrition research in the form of clinical research actions implemented by the teaching hospitals and with contributions from public organizations (Inserm, Inra) with the aim of significantly increasing the consistency of the national commitment to public health research. Lastly, the network recommended promoting the activity of the Human Nutrition Research Centers (CRNH) and developing research areas not yet covered and consistent with the objectives of the PNNS. Economic studies relating to immediate cost-benefit analyses (for example reduction in prescriptions for additional investigations, medication and number of consultations by preventive actions) together with cohort interventional studies were also to be promoted. The PNNS is to be assessed at the end the program (2006).

Research on nutrition and obesity in France

Nutritional research draws on many teams from the EPST research organizations (Inserm, Inra, CNRS) and the universities. A review of the nutritional research forces in France was compiled by Inserm in 2003. A detailed report is available from the Inserm website²². By way of an example, Inserm nutritional research occupies 60 laboratories, 106 researchers, 89 technicians, 9 clinical investigation centers (CIC) and the human nutrition research centers (CRNH) in Lyon, Ile-de-France, Nantes and Auvergne. The budget dedicated to nutrition accounts for 4.8% of Inserm's total budget. The Human Food department of Inra employs 32 teams, 137 researchers, 278 engineers, technicians or administrative agents (ITA) and 110 lecturer-researchers. Several CNRS teams are committed to nutritional research. The term nutrition is included in the subject index of 9 CNRS units. Three of those units have a specific interest in obesity. The ISI study, a world bibliometric study of obesity conducted in 1991 to 2000, provides more specific information on the subject. An evaluation by the Inserm bibliometric unit²³ enables French nutrition research for the period 1998–2002 to be situated.

ISI study on obesity

In all, 19,961 articles (2,045 different journals) were retrieved. There were over 42,000 authors and strong international participation (134 countries). The four journals most cited were: International Journal of Obesity, American Journal of Clinical Nutrition, Journal of Clinical Investigation and Nature. Nature's rank in 4th position shows the scientific community's interest in the subject. The ISI study also enabled ranking by country and number of mixed-citations (table 12.I). Two French studies published by Nature are among the 25 articles most quoted worldwide on the subject.

Table 12.I

Ranking by mixed-citation and by country of obesity research, after the ISI study.

None of the French structures was included among the most productive obesity research centers worldwide: Harvard University, Rockefeller University, University of Texas, Thomas Jefferson University, University of Minnesota, Columbia University, Eli Lilly and Co., Niddkd, University of Pittsburgh, Gothenburg University. In Europe, only Gothenburg University was included among the 10 leading centers.

Nutrition research in Europe, 1998–2002: Inserm study

The results of the Inserm bibliometric study enabled France to be ranked among the European countries (table 12.II). The detailed results are available from the Inserm website²⁴. In short, France ranks second. In terms of excellence (top 1%), France ranks third.

Table 12.II

Nutrition publications in Europe (after the Inserm bibliometric unit study).

The Inserm publications mainly addressed obesity, insulin-resistance, adipogenesis, cardiovascular disease and epidemiological studies. The number of articles in the top 1% was 1.33% for Inserm articles, while for all French articles the percentage was 0.9%. Again, for the Inserm articles, 60% were associated with the hospital environment and less than 10% were conducted without a university or hospital. The Inra articles addressed eating behavior, preventive nutrition, cancer risk and food safety. The subject profile of the publications is shown by country in table 12.III.

Table 12.III

Subject profile of nutrition publications for the various European countries, 1998–2002 (after the Inserm bilbiometric unit study).

The Inserm bibliometric study also enables the subject obesity to be situated for the mixed-citations (table 12.IV).

Table 12.IV

Nutrition study subjects for the European countries, 1998–2002 (after the Inserm bilbiometric unit study).

The international cooperations were ranked, using the Clémentine software package (SPSS). For France, the main cooperation was with the United States, followed by Great Britain and Italy.

Obesity research at the National Research Agency

The creation of the National Research Agency (ANR)²⁶ triggered evolution of the PRNH. Inra, a member of the National research agency, is responsible for management of the 'National program for dietary and human nutritional research' (PRNA). The ANR entrusted Inserm with the operational implementation of evaluation and administration of the dossiers submitted in response to the call for projects: 'Cardiovascular disease, obesity and diabetes'. The ANR GIP program at Inserm was set up in the context of the principles adopted by the board of the ANR and stated on the ANR GIP website.

Strengths and weaknesses of the French initiatives

The setup of the National Nutrition Health Program (PNNS), pursuant to consultation between several ministries, constituted an important advance in the societal awareness of the public health problem and the political determination to respond to it. Obesity is, in fact, only one aspect of the vast program. In the future, the PNNS should define more specific objectives and resources in the field.

Under the impetus of the PNNS, numerous initiatives were taken at national and regional level, reflecting strong reactivity and motivation on the part of the public health players in the field. Several regions initiated prevention programs by mobilizing not only healthcare professionals, the educational community and social players but also politicians and economic decision-makers.

The work of the National Consumer Council and the National Food Council contributed to the reflection on and proposals in the field of nutritional prevention.

With regard to the management of obesity, the recommendations for diagnosis, prevention and treatment (1998), and more recent recommendations on the management of obesity in children and adolescents (2003) received the Anaes label. Some of the French recommendations have been adopted by the European authorities. The Directorate of Hospitalization and Care Organization (Dhos) has defined reception units for obese people. Obesity screening instruments (particularly for children) that are simple to use have been forwarded to physicians and pediatricians by the Directorate General of Health (DGS). The National Health Insurance Organization for salaried employees (Cnam) has undertaken an assessment of obesity surgery.

In the research field, Inserm and Inra, and more recently, the National Research Agency (ANR) have launched nutrition programs including, in certain programs, research on obesity. All the French research teams hold leading positions in terms of the number and quality of the scientific publications on several subject areas at international level.

Despite the great achievements, weaknesses persist, in particular with regard to preventive actions.

The dispersion or even the fragmentary nature of the preventive actions is prejudicial to the overall legibility of the process and raises the question of the consistency of the strategies deployed and their optimization.

Local actions, largely based on voluntary work and dependent on support that is limited in time, remain fragile. The sustainability of financing is a key question in order for the actions initiated to achieve a certain level of efficacy over time.

The insufficiency of rigorous assessment of most of the actions constitutes another weak point. An assessment methodology is to be developed in order to justify and orient resource allocation by the financing bodies.

Opportunities

A series of opportunities is emerging during this period of obesity progression. The opportunities result from scientific work which induced a marked progression in the concepts and practices and enabled definition of action principles. The opportunities are based on a dual community and individual approach and on the commitment of diverse players:

• the concept of prevention exploiting environmental modifications opens up a vast field of action. The prevention, qualified by certain authors as `passive' prevention or `effortless prevention', is based on actions not involving the individual in the first line. The aim is to reduce the environmental pressure by acting on the factors which generate increasing sedentariness and excess calorie intake. This prevention is additional to the preventive actions targeting the subjects at risk and aims to attenuate the constraints to which people who wish to avoid weight gain or reduce their overweight status are subject;
• society's awareness of the issues raised by the progression in the frequency of obesity has given rise to a significant commitment from politicians, healthcare professionals and economic decision-makers with respect to a series of institutional actions;
• the national initiatives are consistent with the European and international programs.

Obstacles

Obesity is greatly dependent on changes in lifestyle and environment. Obesity particularly affects vulnerable populations (children, low-income families, etc.). The obesity prevention and management policy is itself directly related to the socioeconomic and environmental determinants of the disease. The programs encounter obstacles in the form of the persistent and increasing effects of environmental pressure and the socioeconomic determinants which contribute to the development and maintenance of the obesity epidemic. It should also be noted that obesity and obese people are still frequently viewed negatively or even stigmatized.

Obesity prevention thus requires measures that have economic and social incidences. Examples include the question of accessibility, price and quality of foods, major determinants of calorie density and hence of food consumption. The fact that the foods whose consumption should be increased, fruit and vegetables, are the most expensive further increases the social inequalities of health. Similarly, the availability and accessibility of physical exercise facilities and the safety of playgrounds or footpaths for children and families are also associated with economic problems.

The prevention of obesity is clearly a question for health policy. However, the value of an institutional or economic player with respect to preventive policy is far from proportional to the player's influence in the decision-making processes.

Action principles

Obesity is a chronic disease. The preventive and therapeutic responses are to take into account a large variety of progressive and symptomatic situations. Prevention and treatment strategies involve interventions in numerous fields but also actions that are to be differentiated as a function of the stage of the disease. On the basis of that analysis, the working group would like to stress the following action principles:

• earliness: obesity is a progressive chronic disease that tends toward exacerbation through life. In the vast majority of cases, obesity begins in childhood and adolescence. Prevention and treatment are to be implemented early. Special attention is to be paid to the screening for and treatment of children and adolescents. Universal prevention (at population level) must promote education on good physical health (nutrition and physical exercise) as of early childhood;
• overall approach: obesity is a multifactorial disease. Taking into account a single determinant is a vain effort. In terms of public health, an isolated measure will not be sufficient. The actions must be multifocal and multi-sectorial and mobilize the institutional and non-institutional sector and the associations and economic players;
• complementarity: the convergence of the actions and the complementary nature of the interventions are essential. It is not appropriate to contrast `individual' with `collective', or to separate medical actions from societal actions, or to stress one at the expense of the other;
• consistency: the consistency of political actions in the dietary field is a central question. The most critical example resides in the question of the consistency between `nutritional policy' and `agricultural policy';
• progressive nature: the programs must adapt to the progression of the socioeconomic context and scientific knowledge;
• respect for the individual: the greatest vigilance is required in order not to reinforce the stigmatization of obese people through public health campaigns: `act against obesity, not against obese people';
• independence: in such a complex and costly issue, the question of partnerships is crucial. The conditions for cooperation between the public and private sectors must be debated. The independence of actions within clearly defined partnerships must be ensured;
• implementation: the mass of recommendations and regulations in France is already considerable. Their enforcement would induce marked progress (e.g. the regulations on school canteens);
• decentralization: the national political impetus must be relayed at the level of the actions in the field by proximity players in order to adapt the measures to the specific context of the intervention site;
• delegation: new professions or new conditions of practice are to be defined, particularly for nurses and dieticians; promotion of health in schools calls for educational science training;
• sustainability: public health policies in the field of chronic diseases related to the environment call for actions that are sustained over a considerable duration (decades). The action calendars must distinguish the short-, medium- and long-term objectives;
• program assessment: given the lag time for impact on population health, the programs are to be evaluated initially on the basis of interim criteria: acceptance and application of the health promotion messages, durability of the action and its impact. The evaluator must be independent;
• costing: the financing for and cost of prevention campaigns must be clearly determined and known;
• research: the programs must include a population-based dimension and promote an interdisciplinary approach by including the humanities and social sciences. The programs are to link research, actions in the field and assessment. The need for a strategic research plan specifically on obesity needs to be analyzed. That option was adopted by the NIH.

Priority areas for short- and medium-term actions

The areas mainly consist in diet and physical exercise. The actions are to address (non-exhaustive) the immediate environment or `ecological niche', school, care organization, workplace, food industry and communication. The following are to be impacted (non-exhaustive):

• consumer information: regulation of labeling and advertising, nutritional claims and institutional communication; adaptation of the messages and instruments for populations in difficulty and at risk;
• food offer: policy to support low-energy density food offer and targeted consumption subsidies (in catering settings in particular); application of the food regulations to collective institutions and particularly schools; food offer for populations in difficulty and at risk; nutritional quality of foods; portion sizes (food industry, marketing and distribution);
• physical environment: integration of the objectives of the combat against obesity in urban policy and transport policy; sports facility accessibility in schools, universities, the workplace and the urban environment;
• health policy: sustainability and adaptation of the PNNS;
• care system organization: promotion of new professions, reform of the status of dietitians, application of the Anaes, DGS and Dhos recommendations, improved access to care, acquisition of medical equipment suitable for the obese (imaging, etc.), healthcare professional training, reference centers, networks, therapeutic education;
• health monitoring: financing of repeated epidemiological studies on nutritional status at population level; review of screening facilities for, and access to, care for the various subgroups of the population;
• research policy: reinforcement of interdisciplinary research on the determinants and all the consequences of obesity in the calls for projects from the ANR and research organizations.

Developing public health analyses and policies: the importance of being independent of industrial interests

Unfortunately it soon emerged that the development of a coherent approach to specifying an optimum European diet in the Eurodiet project was becoming difficult to establish because of repeated objections from a couple of scientists who had been proposed as suitable contributors to the development of the public health analyses by the food industry. The rest of the group were well aware of the regular funding of these scientists by the food industry – and particularly by the soft drink, confectionary and sugar interests – but their numerous objections and alternative suggestions still had to be dealt with on the basis of reasoned, detailed and often extensive arguments.

The majority of the nutritional scientists and public health specialists were very clear that great efforts were needed to limit the amount of fat, particularly saturated fats, sugars and salt being consumed by Europeans, an analysis in agreement with all other major governmental and World Health Organization (WHO) reports (WHO, 1990, 2003). Once most of the analyses had been agreed a special conference was convened in Crete so that in an open public discussion the public health implications of the reports could be evaluated. Again, however, the French diplomats were dismayed to discover the intensity of the objections to the agreed analyses by industrial groups and how the conference was being misled about supposed official meetings of the Chief Dental Officers of Europe who seemingly had proposed a more benevolent approach to current national sugar intakes. In practice a meeting of some dental officers had occurred but this was a meeting funded by sugar interests and without any official status. Even more disturbing was the continued resistance of official EU representatives from the Commission's Directorate involved with trade to the then agreed official WHO policy on the value of a minimum of 6 months breast feeding. From this experience and the subsequent intense lobbying of the Commission to set aside the Eurodiet conclusions most governments and the Commission have now come to recognize that public health and nutritional analyses together with their policy implications need to be developed completely independently of industrial interests.

This conclusion has been reinforced by the experience of the Bovine Spongiform Encephalopathy (BSE) crisis with which I was completely involved as a scientific expert first for the UK Prime Minister, Tony Blair (James and McColl, 1997) and then for the Commission. The BSE crisis at that stage was so serious that it led to the threat to sack the European President and his Commissioners. The Commission responded with a total reorganization of the Commission's approach to health and the development of DG SANCO with a clear mandate to put the interests of the population's health above the immediate concerns of trade and other powerful lobbies. In the case of BSE we in the Commission's Scientific Steering Committee were constantly under pressure with Chief Veterinary Officers complaining about our conclusions and sometimes seeking our expulsion from our job as we identified one after another EU country as probably having BSE and not taking adequate precautions. The Commission at that stage insisted on the value of our independent analyses and soon realized that their best insurance against charges of neglect was to automatically back our opinions. This approach was rapidly reinforced when we were repeatedly shown to be correct in our meticulously prepared analyses which contradicted most if not all the claims and counterarguments of farming groups and those involved in the distribution and processing of meat products.

This experience of BSE has led the EU Commission in DG SANCO to recognize that scientific analyses and options for policy development in relation to health or other consumer or general public interest need to be developed by a thoroughly independent group of experts. This does not mean, however, being anti-industrial – a common charge when the conclusions do not favor particular interest groups. Indeed industry has a major role to play in being involved in the policy implementation process and in highlighting particular options which would allow the least adjustment to their current practices but still meet the objectives of a new policy. Thus on March 15^th 2005 the Commission announced the formation of a joint Commission/industrial/non-governmental organization (NGO) Platform for the prevention of the current alarming rates of obesity in Europe. All sectors of the European food industry are involved but the Commission is very clear that any nutritional policy needs to be developed by an independent group and not by those with a special financial interest. In keeping with this policy the decision of the French Parliament to commission an independent report from Inserm on possible new analyses of nutritional public health needs in France is to be welcomed.

Nutritional needs for combating obesity and their policy implications

It is only since 1997 that WHO and then many national governments have come to recognize that obesity is now a major public health problem affecting not only North America and Europe, but most of the developing world (WHO, 2000). The European Regional Office of WHO has also now established obesity as its top priority and this issue will be considered by all the Ministers of Health for the WHO European Region in Istanbul in November 2006. It is therefore clear that there has been very little time so far for major initiatives to be undertaken to combat obesity and policy makers should therefore not be surprised by the very limited information that we have on practical community developments which are known to be successful. Governments throughout the world are now exploring what best to do and it should be recognized that developing public health policies to combat obesity is a much more complex process than we originally expected. In the health field policy-makers have come to demand rigorous multiple double-blind trials of any intervention strategy, e.g. for changes in the use of drugs, when introducing new diagnostic tools or other initiatives. However, when we are dealing with the implications of obesity one has to take a much broader perspective. This broader perspective is dependent on recognizing that community intervention projects are much more difficult to conduct than simple drug trials. They also involve many different factors and non-medical sectors which are not readily evaluated in a rigorous, experimental way. Therefore, as with most other aspects of Government policymaking e.g. for social and economic policy making, one has to work on the basis of understanding the causes of the problem, evaluate the primary drivers and then identify suitable options for changing the environment.

Individual or community approaches?

Too often governments and policy makers have considered obesity to be the responsibility of individuals. Surely, they argue, if somebody puts on weight, then they should themselves be able to identify this problem and to prevent any further weight gain and, indeed, return to their previous normal weight by simply eating less and exercising more. Whilst this is biological logical, it neglects the now overwhelming evidence that to assign the responsibility only to the individual is to neglect the huge pressures on the whole of society to put on weight. It is very clear from numerous studies over the last 3–4 decades that obese individuals have been trying desperately to reduce their weight unsuccessfully despite many major educational campaigns, numerous targeting articles in women's magazines and with the popular press focusing on the problem. Despite these efforts and the development of a multi-billion Euro slimming industry the proportion of individuals becoming overweight and obese has gone up inexorably.

Clearly, there are family associations in the propensity of individuals to gain weight. Thus the chances of child becoming overweight are far greater if the child's parents are obese. Whereas traditionally we assumed that this simply reflected bad parenting and the consumption of an inappropriate diet with too little exercise, it has now become clear that families on a similar diet and exercise pattern show very different propensities to weight gain and the genetic susceptibility of different individuals is now well accepted. Thus 20 years ago in France only the very genetically sensitive individuals tended to become obese, but now far more less susceptible people are also becoming obese. It is clear that the genetics of the French population has not materially changed in the last 50 years, so the overwhelming epidemic of obesity has to be of environmental origin. Therefore, to tackle the underlying causes of the epidemic, an environmental approach to prevention is needed and those who gain weight easily need to be in a better environment if they are going to cope effectively with their weight problem.

Why then do obese individuals find it so difficult to return to their normal weight? Under normal circumstances the brain regulates food intake extremely well and we subconsciously adjusts our intake on a daily basis to take account of the variations in the level of physical activity. Thus when somebody puts on weight, this means that the pressures to gain weight have overwhelmed the appetite control system but with a steady 1 kg weight gain each year this still amounts on average to an excess intake of 20 kcal per day, i.e. only 1% of the usual 2,000 kcal daily intake. This small discrepancy highlights just how effective our normal appetite control system is unless we overwhelm it by taking foods which trigger a poorer response in the complex brain control system and this mechanism has to work even more effectively if we are inactive and therefore demanding that the brain mechanism should stop us eating. Thus when people put on weight it is not because they are foolish or unable to control their food intake – all of us have a sensitive and effective system but a system which we overwhelm by living in an inappropriate environment where there are constant inducements to eat and do very little physical work.

Once we begin to gain weight the brain in some unknown way adapts to the weight gain and then "resets" the normal brain control mechanisms so that the normal control of food intake is geared to maintaining the excess weight. This is why very obese individuals who successfully lose weight only manage to keep their weight at a normal level by obsessively monitoring their intake and deliberately undertaking far more exercise than normal. A constant theme of these "post-obese" individuals is their constant hunger and desire to eat; they then have to go to very special lengths to stop themselves eating when there are so many temptations provided everywhere to eat and drink more than they need. They are also handicapped by their environment where we have all become used to using motor cars, computers, mechanical aids at work and at home. In fact, it is very unusual for anybody now to have to engage in heavy physical work: most of us can earn a very good living without having to be physically active at all.

Thus individuals who are genetically sensitive to obesity are now in particular difficulty because their whole environment is geared to promoting weight gain. This dilemma highlights the fundamental importance of taking a prevention approach to obesity and indicates that in obesity-prone families they will need to systematically develop their own micro-environment to resist the pressures to eat too much and to exercise too little.

The burden and health costs of obesity

In a recent analysis for WHO we assessed the health impact of excess weight gain in different parts of the world (James et al., 2004). Figure 1 shows the burden in different parts of Europe, this burden being calculated in terms of the number of Disability Adjusted Life Years (DALYs) lost and the reasons why overweight people either die early or become sick and disabled. Although there are over 50 complications of excess weight gain and obesity, we only had very clear data on the greater rates of ischemic heart disease (IHD) high blood pressure (HT), stroke, diabetes and 3 forms of cancer, i.e. colon, post-menopausal breast and endometrial cancer. We were able to add the problem of arthritis induced by weight gain, but could not take account of all the other disabilities that relate to excess weight e.g. backache, respiratory impairment and numerous other conditions. Figure 1 shows that in the Euro A region, which includes France, there are nearly 2 million lives lost or disabled each year in both men and women due mainly to the cardiovascular disease and diabetes induced by excess weight gain. In these calculations no separate national analyses were made, but it is clear that these estimates need to be looked at both in terms of the recognized huge increase in the health burden that is likely to occur in France and elsewhere over the next 20 years and, indeed, the economic costs of the health burden. So far we have failed to recognize the health costs of obesity which the UK National Audit Office (National Audit Office, 2001), the British Parliamentary Health Select Committee (House of commons health Committee, 2004) and, indeed, the UK government's own special economic advisor, Derek Wanless, have recently highlighted (Wanless, 2004). Indeed these costs are probably major underestimates because it is now becoming evident that we have failed to take account of just how much the escalating epidemic of diabetes will impact on the problem of kidney failure: there is going to be a huge increase in the demand for kidney dialysis. The cost of dialysis is estimated at 40–50 thousand Euros per year for the dialysis part of the medical care alone and already up to a half of all patients in dialysis units have diabetes as the underlying cause. Type 2 diabetes is now so closely linked to excess weight gain and obesity that the term "diabesity" has been coined to emphasize the intrinsic linkage. Our own analyses of the time when the burden from overweight and obesity is at its greatest shows that it is in the 45–59 year old group where the maximum disability is evident, i.e. during the economic working life of the population. Indeed, over 70% of the total burden is seen in those below the age of 70, so this is not a problem of the very old: it is a problem which is already affecting the working capacity of the population. The UK government has very recently assessed the impact of obesity as already leading to an average reduction in the UK population's life expectancy of 2 years (Department of health, 2004).

Figure 1

Disease burdens in Europe linked to increasing body weights. The DALYs are calculated on the basis of the years of life lost and the years of disability induced every year in that proportion of the population which is above the optimum average corresponding (more...)

Developing a physical activity prevention strategy: the need to redesign our towns and cities to allow routine walking and cycling as part of every-day activity

Developing a strategy depends on a clear analysis of the underlying causes of the obesity epidemic. First, consider the problem of physical activity where it is now clear that the old idea that we should engage in perhaps 30 min of moderately vigorous activity e.g. fast walking, 5 times a week does indeed help to reduce the risk of cardiovascular disease but to prevent weight gain, particularly after some weight loss, then 60–90 minutes extra walking is needed for the majority of the population (Food and Agricultural Organization of the United nations, 2001). Now the pressures to remain without physical activity are many including all the easy transport systems, the work environment and the inducements to stay at home, watching television or working with games and other internet systems.

Given these huge environmental changes no one would suggest that these developments be reversed but we need to recognize the billions of Euros of public and private investment in the reorganization of the transport systems of all developed countries with a road and urban redesign which has been primarily to ease and speed the flow of motor cars. So how should we respond? There has already been an attempt to encourage people to exercise more, to engage in sports and other recreational activities. In response to this campaign it is clear that sub-groups within the better educated and wealthier sector in our societies do develop a new leisure time approach to physical activity. Special leisure centers have been constructed with appreciable numbers paying extra for the privilege of access. However, almost everywhere it is clear that the numbers actually engaging in routine physical activity are small and on a population basis there is no evidence of a systematic increase in physical activity patterns. Furthermore the emphasis on an educational approach to taking extra physical activity during leisure time impacts only on a minority; the main beneficiaries are those in the higher social class who have the ability and resources to alter their lives despite all the current constraints on routine physical activity in our daily life. Thus the routine demand to tackle the problem of obesity by educational campaigns will in practice increase the social divide and not help the poorer and more disadvantaged sectors of the population. It is therefore clear that in the modern world we need to recreate an environment where there is the opportunity to take physical activity routinely as part of daily living, not as an extra conscious decision which has to be made when there are so many other conflicting pressures.

The magnitude of the change in activity patterns can be seen in the steady collapse in physical activity with time and the almost routine fall in physical activity as people age. Some years ago we calculated that in the US there had been a fall amounting to 1,200 kcal per day in the energy used by men as they passed from a very active sporty life when they were 25 years old to the time when they were retired at 75 years of age (James et al., 1989). During this time mechanization was in full swing so the secular decline of the whole population's activity was being amplified by the age related decline in spontaneous or sports related exercise. What this therefore means is that there will be an inevitable weight gain unless the same individuals - and indeed the total population systematically reduces their intake by many hundreds of kcal per day with a total drop for the elderly amounting to 1,200 kcal per day! It is not surprising therefore that as men and women give up sports in their early 20s then they gain weight progressively.

Urban design

Some cities, e.g. Copenhagen, Aarhus, Barcelona and many cities in the Netherlands are being maintained or redesigned to provide streets that are safe for children to play routinely outside the home, with special cycle paths and walkways for children to walk or cycle to school and where the elderly feel safe when they walk or cycle short distances to do their shopping. The design of cities with out-of-town supermarkets was an excellent idea for the interests of the supermarkets, but the public benefit was mainly felt by those with cars and the financial ability to shop once a week and store their food in large refrigerators. The poor with no transport and a family to feed found the small local shops disappearing or providing limited sources of food at higher prices. We need therefore to recognize that the decisions of local authorities on the development of congenial town centers with measures to facilitate local shops and with city centers for pedestrian and cycling only can be substantial contributors to an environment where physical activity is a routine rather than a special leisure time issue.

Workplace policies to facilitate cycling and walking to work rather than car use

The French government and French local authorities as well as the business community could encourage physical activity by providing facilities at work which make it easier for people to cycle to work, store their bicycles, if need be take showers, and also possibly engage in physical activity at lunch time or after work. If one calculates the number of people employed by the public sector, then it is clear that the public sector could take a lead in changing the whole culture relating to physical activity. The business community could also be engaged if studies were undertaken to demonstrate to them the economic benefits that would arise if their employees were more active. Thus it is clear from a number of studies that both men and women feel better if they have been physically active and they then find it easier to work. Furthermore, there is now very substantial evidence to suggest that one can make a major difference in limiting the effects of high blood pressure, the development of diabetes and indeed of some cancers if people are more active. There are also a few studies which suggest that by encouraging physical activity the absenteeism and need for leave from work for hospital appointments etc. can be reduced. Given the fact that the major burden on European societies from obesity comes before retirement age and that physical activity is now clearly demonstrated to be of benefit, we need to take a very different strategic approach to providing the facilities and environment which positively encourages physical activity and limits routine car use.

The issue of schools will be dealt with separately.

The dietary challenge in France and the rest of Europe

There have been a number of major studies conducted by French investigators showing the value of a Mediterranean diet. New studies on the elderly reinforce the benefits of the Mediterranean diet which was characterized by substantial fruit and vegetable intake, i.e. a minimum of 400 g/day for every man, women and child. Traditionally the meat, milk, fat and sugar intake in the Mediterranean area was very low. Only in Greece was there a higher olive oil consumption and this population was heavier than the rest of the Mediterranean community when originally studied by Ancel Keys and his colleagues in the 1950s (Keys, 1980). The French culture, with its emphasis on the quality of food and the importance of regular family meals has probably made a major contribution to why the burden of disease in France and the obesity rates of the French have been lower than in many other European countries. Now, however, as described elsewhere by Inserm there is alarming evidence of an increase in overweight and obesity rates and this is now particularly affecting children. It would appear, therefore, that the French cultural tradition is being systematically destroyed by those forces that benefit when they successfully market new foods and soft drinks which are rich in fat and sugar and are therefore very dense in energy. This energy density, particularly when snacks and drinks are eaten between meals makes it extremely difficult for the normal brain mechanisms to control the body weight by shutting down food intake (Drewnowski, 1998; Stubbs et al., 1998; Raben et al., 2002; Prentice and Jebb, 2003). We therefore have in France at present a population where the normal brain mechanisms are telling the French to eat less because they are so physically inactive whilst at the same time the supermarket, retailing and other food sector strategies are encouraging the consumption of very inappropriate foods and drinks which do not conform with the quality of the traditional French cuisine. Again, therefore, as with the problem of physical inactivity, the idea of simply telling people to return to the marvels of traditional French cuisine naively neglects the huge pressures on society to "modernize" the French diet, this in practice meaning an encouragement to eat a far more obesity generating diet. The brain has particular difficulty in detecting fat in the diet and free sugars, especially if fats and sugars are taken between meals.

The price and availability of foods determines their consumption: implications of the Common Agriculture Policy

The evidence from behavioral studies on smoking, alcohol use and eating patterns all show that there are two fundamental factors which strongly influence the behavior of a population, i.e. the price of a commodity (French et al., 2001) and the availability and marketing of these products. We must remember that the enormous benefits of the Common Agricultural Policy came when the needs of the poor farming community were matched with our original nutritional and health perceptions that children benefited from an ample supply of animal protein, e.g. in meat and milk, with sufficient energy being provided to ensure that even the poor could have enough to eat. The Post-War "cheap food policy" was introduced globally and the French government, as well as the other countries of the European community, have systematically subsidized the farming and food business in an effort to improve not only national food security but the well-being of the poorest in the community as well as the farming sector. As a result of many decades of huge subsidies for research and development and direct subsidies to encourage the production of meat, milk, cereal production (for animal feeding), oil and sugar production, France and the rest of the European community has an agricultural policy which is no longer geared to public health. Thus our agricultural colleagues recognized many years ago that farmers in the Mediterranean area would benefit from an increase in the price of fruit and vegetables and so they systematically funded from Brussels the destruction of most of the fruit and vegetables crops being grown in the Mediterranean (Robertson et al., 2004). This led to an increase in price which benefited the farmers but the higher price is a well-documented critical factor in limiting the choice of fruit and vegetables, particularly by the poor.

This example is simply used to show that industrial policies have a huge effect on health whether we are discussing transport and urban planning policies in relation to physical activity or agriculture and food policies in relation to the nutritional quality of the diet.

Post-war food industrial strategies

One of the major features of the post-war era is the huge development of the food and soft drink industries in North America and Europe. They have developed brilliantly by using a series of strategies to promote their sales:

• lower prices;
• ensuring that as many as possible outlets are available to the public;
• developing brands to promote their marketing;
• super sizing;
• focusing on preschool children marketing to induce brand loyalty;
• selling their products in countries where they have low sales.

Originally food companies competed with each other by targeting the price of their commodity and to this day supermarkets highlight the price advantage of people buying from their particular supermarket chain. The food industry then realized that they could gain extra marketing advantage by ensuring that their products were available anywhere. Thus McDonalds in the US developed a strategy where everybody should be within a 5 min drive of a McDonald's restaurant and the same strategy is evident for all the major food companies. Then the marketers recognized the value of developing special brands of food; the marketing of brands has become a major preoccupation of most western industries. Following this there was the idea that one could market more effectively by "super-sizing", i.e. providing 50 % more or even twice as much for only a small increase in price. It is now well-documented that the bigger the portion of food presented to children over the age of 4 and to adults, the more they will spontaneously eat. When super-sizing was having no more impact, food companies and their advertising agents marketed the brands to children because they discovered that children could have a profound influence on their parents' purchases and supermarkets learned the tricks needed to persuade their parents to buy particular food, confectionery and soft drinks.

Now the next industrial strategy for most big food companies is to target those areas of the Mediterranean and developing countries where their products are not yet being consumed. This has therefore led to a dramatic reduction in the quality of the Mediterranean diet with a marked increase in fat and sugar intakes. This has particularly affected children so that in many Mediterranean countries the children now have hamburgers, fried foods, soft drinks, sweets, chocolate and biscuits. They are being targeted with the idea that snacks and soft drinks and fast foods are an appropriate part of an enjoyable life and new evidence is emerging that children are no longer being brought up in the traditional environment where they would be exposed as a routine to set meals rich in fruit and vegetables with very few high fat foods and practically no added sugar. It is now well recognized that children need to be exposed to vegetables and fruits for up to 15 times before they accept these foods as a normal part of their diet. Fats, sugars and salt, however, are tastes for which we have primitive drives with special taste buds and mouth sensing systems geared in evolutionary terms to targeting these sources of energy and salt needs. Now, however, these primitive drives are being used to market products because taste panels routinely show the attractiveness of products rich in these ingredients.

Developing prevention strategies relating to the quality of food

Figure 2 shows a general scheme for providing a coherent approach to changing the environment both in terms of physical activity and diet. The emphasis so far has been primarily confined to the idea that an educational approach is all that is necessary, but the latest rigorous Cochrane analysis shows that advice to individuals, even given by doctors has, as a population approach, very little effect (Brunner et al., in press). Thus we have to now focus on changing the environment at a physical, economic, political, i.e. legislative and regulatory level, as well as considering how best to change the accepted cultural perceptions of fast foods, snacking, soft drink consumption and eating on the move, all of which are conducive to weight gain. Table 1 provides an indication of how food pricing and availability policies could be developed progressively over a 5–10 years period. Indeed the French parliament, with its traditional concern for both the quality of French food, its cultural associations and the well-being of farmers could make a major contribution to spearheading a new approach to obesity prevention in the European Community.

Figure 2

Societal policies and processes influencing the population prevalence of obesity. This figure illustrates the numerous factors and sites which in practice influence the choice of activity and foods by individuals. Therefore no one solution to the problem (more...)

Table I

Food "availability" and pricing policies.

Food labeling

Food labeling is but one example where the idea that the public is able to discriminate the quality of food on the basis of the current labeling system has proven to be wrong. Repeated consumer surveys show that consumers cannot understand the labels which are set out in technical jargon and the idea of specifying what an average man or women needs in terms of energy is not only wrong and misleading, but ludicrous! The energy needs of children and adults can vary threefold and if the public, with great difficulty, managed to follow the advice implied by the need of women for 2,000 kcal and men for 2,500 kcal, then if these were the average need of French men and women, which I doubt, then by following the advice meticulously almost half the French population would start gaining weight, and almost half losing weight. This is why the British Parliamentary Health Committee on the basis of extensive consumer research and analyses by the Food Standards Agency of the UK (Rayner et al., 2004), advocated the use of a traffic light type of signaling system whereby consumers could distinguish the overall quality of the food itself based on scientific analyses of the food's quality in terms of fat, sugar and salt. A red signaled food should be eaten sparingly, green labeled foods in abundance and yellow labeled foods in moderation. Currently the European Commission is considering the need to have some simple method which highlights the nutritional and health quality of a food but all too often food companies are only interested in marketing their good foods as "functional foods" of value, whilst ignoring the fact that many of their products should be eaten sparingly, if at all. The nutritional profile of foods is important and it is no longer possible for industrial interests to argue that there are no good foods or bad foods; by definition if one food is considered better than another for its nutritional and health properties, then it should be possible to a develop a uniform and systematic labeling of foods, and certainly of particular dishes in canteens, the workplace, restaurants as well as in supermarkets.

Table 2 shows a proposed list of strategies for helping to prevent obesity in children and a list of policies in schools which have been proposed and/or tried successfully. There is ample evidence that children below the age of about 12 have not yet developed the ability to make an appropriate judgment where they can discriminate between a marketing message geared to their immediate desires and a more rational long-term and coherent view of the different opinions that one will encounter in everyday life. Thus experts in child psychology and pediatrics have emphasized the importance of creating an environment which is appropriate for a child's learning. Currently it seems to have been accepted that the unbridled marketing of products to children is acceptable when this in practice is manipulating children's behavior for the benefit of the marketer without regard to the long-term welfare of the child. This is not a controversial judgment but was clearly set out in a special report which took account of the world's literature on the ability of children to understand the information that they receive on food. It became clear after consulting about 30,000 published references that the marketing of a brand not only enhances the demands of children for that selected item, but it also increases their desire for the category of products, e.g. soft drinks, which are being marketed. This in turn leads to a change in the categories of food consumed and a distortion of the nutritional quality of a young child's diet. It has been recognized for a long time that children brought up in a very organized and socially-advantaged environment are able to maintain their activity and food patterns much more effectively, despite external pressures to change, providing that they are protected from inappropriate influences before they go to school and throughout the primary school period. Only when they are going through their adolescent development does the normal interplay of the home environment and external influences become an issue. Therefore it is clear that we have, in the last two to three decades, failed to understand the fundamental importance of protecting our children from the inappropriate marketing of foods which are disadvantageous to their health. Overweight children already show the accelerated responses indicative of the early phases in the development of diabetes and high blood pressure. Thus the progressive increase in the rates of overweight and obesity in France should be of major concern. It is obviously completely inappropriate to blame the child and the idea that parents have complete control over the well-being of their children is no longer true when so many families have both parents at work. Table 2 summarizes the variety of initiatives which can be undertaken to change children's environment.

Table II

Strategies for combating childhood obesity.

Conclusions

It is no longer possible to argue that an educational approach to individual behavior is the answer to the obesity epidemic. French children need to be protected and the biggest drive in educational terms should be not simply to the school children but to policy makers in the areas of fiscal, agriculture, retailing, transport, urban design and education policies. Table 3 simply summarizes the fact that one should not only think of the Ministry of Health as responsible for the obesity epidemic: the other Ministries of Government have a far greater influence on the development of the obesity epidemic than the Health Ministry. The Ministry of Health is now trying to cope with the immensely deleterious effects of other government departments' policies over several decades. The French nation, like other western countries, will not be able to afford the escalating health costs. Without a new strategy approach with multiple interventions in many different sectors, it is unlikely that we can stem the obesity epidemic. There is no single magic bullet and a coherent plan is now needed with a careful monitoring and evaluation of the different initiatives. Other governments, e.g. Sweden, have just produced their new plan of action and France has an opportunity once again to lead the European Community in developing new strategies of benefit to even the poorest in society.

Table III

The Stefani model: a few examples of strategies for effective nutritional initiatives to illustrate the different dimensions of policy needed.

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