CRD summary

The authors concluded that a combination of training, behaviour therapy and diet produced the best weight loss in overweight and obese healthy adults. Methodological limitations that included the likelihood of missing studies, failure to consider study quality, lack of details of review methods and limitations in the results mean that these conclusions are unlikely to be reliable.

Authors' objectives

To determine the effectiveness of physical exercise/activity with or without diet and/or behaviour modification for the treatment of overweight and obese healthy adults.

Searching

MEDLINE, The Cochrane Library, PEDro, CINAHL, AMED and AMEDEO (Free Medical Literature Guide) were searched for studies published in English between 1995 and 2006. The authors stated that studies published before this were included in previous reviews. Search terms were reported.

Study selection

Randomised controlled trials in which at least part of the intervention consisted of physical training or exercise, that enrolled at least 15 overweight or obese healthy adults in the treatment group and that had duration or follow-up of at least 12 months were eligible for inclusion. Interventions evaluated in included studies consisted of aerobic training, mainly in the form of walking (some studies evaluated step-up, jogging and cycling). Some studies combined aerobic training with strength training, diet and/or behaviour modification therapy. Most studies used a combination of individual and group training; one comprised individual training only. Duration of the training session was poorly reported. Training sessions were carried out on two to seven days a week. Intensity varied from easy to difficult. Duration of the training period varied from 16 weeks to two years. Control groups consisted of training alone or no intervention. Most studies were conducted in women, one was conducted in men and four included both men and women. Mean age ranged from 37 to 57 years.

The authors stated neither how the papers were selected for the review nor how many reviewers performed the selection.

Assessment of study quality

The authors did not state that they assessed validity

Data extraction

The authors stated neither how data were extracted for the review nor how many reviewers performed the data extraction.

The effect size was calculated by dividing average weight change following the intervention with the standard deviation before the intervention. Effect sizes were calculated at the end of the intervention and at the end of follow-up.

Methods of synthesis

A narrative synthesis was presented.

Results of the review

Twelve studies were included in the review (n=1,385).

Seven studies reported that body weight decreased significantly more in the intervention group compared to the control group. In two studies, weight increased at the end of the intervention period. Effect sizes were greatest in two studies that combined diet with aerobic training. There were significantly lower weight gains at follow-up of up to two years in studies that included moderately intense aerobic training and emphasised increased individual daily activity. Three studies reported no significant differences between intervention groups at follow-up.

Three studies provided information on changes in body composition. Two studies reported a significant decrease in fat-free mass in groups that combined diet, aerobic training and behaviour therapy. The third study reported a significant decrease in the ratio of waist and hip circumference among those randomised to resistance training compared to those in the walking group.

Six studies assessed training effect measured by maximum oxygen uptake capacity (VO₂ max). Four studies reported positive effects for all training groups. One study reported no changes in any intervention groups. Results for the remaining study were not reported.

Authors' conclusions

The treatment that produced the best weight loss included a combination of training, behaviour therapy and diet.

CRD commentary

The review addressed a clear question supported by inclusion criteria defined in terms of intervention, study design and participants. The literature search was adequate for published studies, but restriction of the review to published English-language studies meant that there was a possibility of language and publication biases. Only studies published after 1995 were included as the authors stated that earlier studies had been included in previous reviews, but details of these studies/reviews were not included. Details on the review process were not reported and so it was not possible to determine whether appropriate steps were taken to minimise bias and errors. Study quality was not evaluated and so the reliability of the included studies was unclear. A narrative synthesis may have been appropriate given the differences between studies in terms of interventions and comparator treatments; however, further statistical details would have helped interpretation of results. Although some effect sizes were provided in tables, these were difficult to interpret, did not relate to comparisons across treatment groups, did not include baseline data and confidence intervals were not provided. The text consisted of a purely descriptive report of study findings with very little numerical data. In view of the many methodological limitations of this review, the conclusions are unlikely to be reliable.

Implications of the review for practice and research

Practice: The authors stated that treatment of overweight individuals required a multidisciplinary approach. Representatives from all professions must collaborate with each other. It was important to choose training modes and intensities that are well suited to participants.

Research: The authors did not state any implications for research.

Funding

Not stated.

Bibliographic details

Soderlund A, Fischer A, Johansson T. Physical activity, diet and behaviour modification in the treatment of overweight and obese adults: a systematic review. Perspectives in Public Health 2009; 129(3): 132-142. [PubMed: 19514637]

Original Paper URL

http://rsh.sagepub.com/cgi/content/abstract/129/3/132

Indexing Status

Subject indexing assigned by NLM

MeSH

Behavior Therapy; Diet Therapy; Exercise Therapy; Humans; Obesity /therapy; Overweight /therapy; Randomized Controlled Trials as Topic; Weight Loss

AccessionNumber

12009105797

Database entry date

24/03/2010

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.