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Poos MI, Costello R, Carlson-Newberry SJ; Institute of Medicine (US) Committee on Military Nutrition Research. Committee on Military Nutrition Research: Activity Report: December 1, 1994 through May 31, 1999. Washington (DC): National Academies Press (US); 1999.

Cover of Committee on Military Nutrition Research

Committee on Military Nutrition Research: Activity Report: December 1, 1994 through May 31, 1999.

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations

The Committee on Military Nutrition Research (CMNR) has reviewed many studies over the past 10 years on the relationship of nutrition to performance in all aspects of life—both on the job and during relaxation. Food is provided for military personnel on the military bases through garrison dining facilities and during field operations through a variety of military operational rations. In garrison, soldiers can choose to eat in the military dining halls, eat at home with their families, or eat in restaurants similar to the American civilian population. In the field, food selection is limited to the operational ration available during the mission. The nutrient level in military food—whether offered in military dining halls or packaged in military operational rations—is guided by the joint Tri-Services Regulation, AR 40-25 (1985). This regulation includes nutritional allowances and standards for active military personnel (the Military Recommended Dietary Allowances [MRDAs]), nutrient standards for operational and restricted rations (for example, survival rations), military menu guidance, and a chapter on nutrition education. The MRDAs are based on the Recommended Dietary Allowances (RDAs) developed by the FNB to provide for the basic nutritional needs of all healthy Americans (NRC, 1989b). The military operational rations are thus designed to provide a healthy diet for military personnel that includes additional energy and nutrients as may be needed to perform heavy work or meet the demands of environmental extremes.

Unfortunately, in training and field operations, military personnel often do not eat their rations in amounts adequate to meet energy expenditures. Consequently, they lose weight and potentially risk loss of effectiveness both in physical and cognitive performance. The U.S. Army's concern about potential performance degradation has led to a consideration of the cause of this underconsumption in the field.

In March 1993, the CMNR was asked to assist a collaborative program between scientists at the U.S. Army Research Institute of Environmental Medicine (USARIEM) and the U.S. Army Natick Research, Development and Engineering Center (NRDEC, who develop food products and test their acceptability) by reviewing recent research in military settings that addresses these issues, coupled with more general research on the effects of the following on food intake: physiology (hydrations status, biological rhythms), the food itself (quality, quantity, variety, learned preferences, food expectations), food packaging and marketing, and social factors (the eating situation, food appropriateness, social facilitation and inhibition). The purpose was to (1) evaluate whether the consistent energy deficit recorded in military personnel in field settings could significantly affect performance and (2) discuss potential strategies that could be used by the military to reduce underconsumption.

The CMNR was asked to consider the results from military research and from the other studies and also to address the following five questions posed by the Army about soldier underconsumption.

1.

Why do soldiers underconsume (not meet energy expenditure needs) in field operations?

2.

What factors influence underconsumption in field operations? Identify the relative importance of rations, environment, eating situation, and the individual.

3.

At what level of underconsumption is there a negative impact on physical or cognitive performance?

4.

Given the environment of military operations, what steps are suggested to enhance ration consumption? To overcome deficits in food intake? To overcome any degradation in physical or cognitive performance?

5.

What further research needs to be done in these areas?

The committee was aware of the complexity of the issue, in particular the question of when a reduction in intake of rations becomes detrimental and can be labeled underconsumption, and at what point undernutrition leads to a decrement in performance. The CMNR decided that the best way to review the state of knowledge in this disparate area was through a workshop at which knowledgeable researchers could review published research with the committee. The workshop therefore was convened on November 3–4, 1993 to assist the CMNR in responding to the Army and provide background information useful for developing its report.

The committee's report, Not Eating Enough, Overcoming Underconsumption of Military Operational Rations (IOM, 1995a), provides responses to the five questions the CMNR was asked to address and includes conclusions and recommendations, as well as recommendations for future research. The report also includes the 20 invited papers presented at the workshop.

Conclusions and Recommendations

On the basis of the workshop presentations and subsequent discussion by the committee in executive session, the committee concluded that underconsumption in the field may affect the performance of military personnel, particularly if it is associated with rapid weight loss (in excess of 2 lb/wk) in lean, fit individuals with little body fat. Rapid redeployment of troops may not permit regaining lost weight between missions.

Since the goal of field feeding is to provide sufficient water, food energy, and nutrients to maintain the soldier's hydration status, body weight, and lean body mass, the committee recommended that a field feeding doctrine should be crafted that incorporates the types and amounts of food offered, issues related to environmental extremes, and actions to be taken with excessive weight loss in the field. From a policy standpoint, the risks that energy deficits will be compounded by uncontrollable events in combat are considerable, and thus any consumption deficits are undesirable. The guiding principle of this field feeding doctrine is that the energy intakes of military personnel during training and combat operations should be adequate to meet their energy expenditures. The level of individual body weight loss should determine the actions to be taken.

While underconsumption of operational rations in the training environment is not likely to result in significant reduction in physical or cognitive performance, it may be indicative of a more severe problem when soldiers are under the extreme stresses of impending or actual combat. Therefore steps to minimize underconsumption in training environments may be important when the stress of actual combat operations are imposed.

Additionally, the CMNR recommends the following:

  • Ensure that energy intakes match energy expenditures
  • Keep soldiers well-hydrated to avoid a decline in appetite due to dehydration.
  • Continue efforts to enhance all military rations.
  • Provide guidance to commanders regarding the effects of underconsumption on performance and how to minimize the adverse effects of the field environment on food intake.

Areas for Future Research

The information in this report is primarily derived from data collected during field training exercises. While these observations are important, the impact of the actual exposure to the stresses of combat or impending hostile action is certainly likely to be much greater. Carefully evaluated feedback from soldiers who were deployed in operations such as Vietnam, Desert Storm, and possibly Somalia and Panama could add further insight and realism to the possible extent of underconsumption and influencing factors (e.g., the degree of anxiety, fear, and climatic condition) that would go beyond the information obtained in training exercises. Acquiring information on the coping mechanism used by soldiers under these conditions may be useful in considering how to overcome these problems and suggest important areas for research.

The CMNR recognizes the concern that the loss of weight by personnel during training and operations poses to the military. The scientists at USARIEM and NRDEC have conscientiously followed this issue and conducted carefully planned research programs that have evaluated the impact of food-intake patterns on performance and the factors influencing food intake. The committee made suggestions for future areas of study that would build on this excellent research base.

The committee also commends the development of Kitchen Company Level Field Feeding-Enhanced (KCLFF-E) equipment and the concept of having cooks forward with combat units. After implementation, this system requires follow-up evaluation as to its effectiveness and ways it can be improved.

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The full conclusions and recommendations from this report are included in Appendix C.

Copyright 1999 by the National Academy of Sciences. All rights reserved.
Bookshelf ID: NBK224673

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