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Conclusions and Recommendations

Not Eating Enough, 1995

Pp. 41–54. Washington, D.C.

National Academy Press

As stated in Chapter 1, the Committee on Military Nutrition Research (CMNR) was asked to address five specific questions dealing with strategies to overcome underconsumption of military operational rations. The committee's responses to these questions appear below. These answers are further elaborated in the recommendations that follow. The conclusions and areas for research developed by the CMNR are also included.


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

Ration factors, including palatability, variety, and temperature of the foods, are major contributors to general acceptance. Heavy activity or environmental extremes may increase energy requirements without compensating ration intake. Hypohydration may lead to temporary anorexia and a worsening cycle of lowered water and food intake. However, environmental or logistic components that are often under the influence or control of the command are

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations 2 Conclusions and Recommendations Not Eating Enough, 1995 Pp. 41–54. Washington, D.C. National Academy Press As stated in Chapter 1, the Committee on Military Nutrition Research (CMNR) was asked to address five specific questions dealing with strategies to overcome underconsumption of military operational rations. The committee's responses to these questions appear below. These answers are further elaborated in the recommendations that follow. The conclusions and areas for research developed by the CMNR are also included. ANSWERS TO THE QUESTIONS POSED TO THE COMMITTEE 1. Why do soldiers underconsume (not meet energy expenditure needs) in field operations? Ration factors, including palatability, variety, and temperature of the foods, are major contributors to general acceptance. Heavy activity or environmental extremes may increase energy requirements without compensating ration intake. Hypohydration may lead to temporary anorexia and a worsening cycle of lowered water and food intake. However, environmental or logistic components that are often under the influence or control of the command are

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations also extremely important. These factors include such situational elements as designation of eating locations, meal schedules, social setting (alone or with others), and provision of rations at appropriate temperatures. The committee believes that multiple logistic, situational, and sensory factors contribute to decreased consumption. Military operational rations are by design all inclusive and do not allow substitution or choice. Failure to provide adequate time, instruction, and encouragement to eat and drink can materially influence consumption. The attitude of the local commander is critical in ensuring that soldiers are aware that daily adequate nutrition is important so as not to degrade performance over a period of time. It would be an important future research step to provide a priority order for the impact of these multiple factors on soldier food intake in the field. 2. What factors influence underconsumption in field operations? Identify the relative importance of rations, environment, the eating situation, and the individual. A number of factors influence the quantity of operational rations consumed. Generally under field conditions, an underconsumption of rations is observed, which leads to weight loss. Numerous factors including the environment, the specific eating situation, the ration itself, and the individual can affect the amount of rations that will be consumed. Any one of these can be the most important factor depending on the situation. Further review of the relevant military data on eating situations that provides an integrated overview of the ordering of environment, the rations, and the individual factors with situational change would be beneficial. The following are reasonable conclusions/opinions based on available evidence: Environment: Field environments are generally harsh, frequently require increased energy expenditure, and are not conducive to the enjoyment of eating. Proximity to danger, temperature extremes, unappetizing local conditions, and lack of protection from the elements are all conditions that are encountered in a military scenario and can contribute to an impairment of appetite and underconsumption. Eating Situation: The opportunity for social interaction,information exchange, and appropriateness of meal to the time of day, are all elements of the eating situation that can contribute to food intake. Rations: Acceptability of rations to the soldier includes temperature,sensory properties (taste, smell, texture, color, and temperature), packaging,individual food preferences, ease of use, nutritional content, stability of product, appropriateness to time of day, delivery, presentation,

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations availability, variety, and duration of reliance on operational rations as a major source of available food. Individual: The individual soldier's attitude toward military feeding systems is an important determinant of ration consumption. The commander's attitude regarding the feeding system and his or her knowledge of nutrition may influence the soldier's eating behavior. Activities of the individual soldier, such as consuming adequate fluids,drinking when eating, taking advantage of opportunities to heat appropriate ration components, and snacking on certain ration items when opportunities permit, will enhance energy consumption and nutrient intake. 3. At what level of underconsumption is there a negative impact on physical or cognitive performance? Underconsumption of fluid or working in hot environmental conditions, either as a result of protective clothing or atmospheric conditions, may result in weight losses of 3 to 5 percent in less than 48 hours and can significantly reduce physical and cognitive performance. Therefore maintaining adequate hydration is critical to maintaining performance. Existing historical and experimental data indicate that decrements in physical performance begin in well-hydrated individuals when 10 percent or more of initial weight has been lost. Other studies suggest that losses as great as 15 percent do not result in decrements in physical performance, if lean body mass is preserved and if the weight loss is primarily from body fat stores. Similarly, decrements in cognitive performance appear to begin to occur when weight losses reach 10 percent of baseline. It is likely that greater losses of body fat will not affect cognitive performance, if lean body mass is preserved. There is only limited, well-controlled research available, however, that addresses this issue. With both physical and cognitive performance, the key factors that must be considered are the initial body composition of the individual and the rate of weight loss. Active military personnel who meet the height and weight standards for their age are relatively lean with some soldiers having as little as 10 percent body fat. Rapid weight loss (in excess of 2 lb/wk) in such lean individuals indicates significant underconsumption with regard to energy expenditure and can be expected to lead to decrements in performance. Intakes of protein in excess of normal intake may help preserve muscle mass in circumstances of inadequate energy intake but will not totally prevent its loss. Adequate carbohydrate intake, particularly during or following periods of heavy physical activity, will aid in maintaining or restoring muscle glycogen and maintaining performance.

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations 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? Adequate fluid intake to prevent dehydration is the first step to prevent or overcome deficits in performance since the consequences of dehydration are most immediate. In addition, as noted in the foregoing discussion, there are many other factors affect ration consumption in the environment of military operations. They include, but are not limited to, the nature of the rations; the eating situation in which such rations must be consumed; the environmental conditions that influence how, when, and under what physical conditions (i.e., temperature) the rations will be consumed; and the motivation provided the soldier to consume the food. To overcome possible effects of underconsumption on physical and cognitive performance, efforts should continue to increase the overall consumption of rations by military personnel in the field through a variety of approaches, which include establishing a field feeding doctrine at all levels within the command structure down to the individual soldier. Such a field feeding doctrine would include definitions of adequate food intake for soldiers in military operations and the potential consequences to performance and health of not eating enough. Steps to assure that soldiers have adequate intake should also be outlined in the food doctrine. Military operational rations must be designed so as to protect body weight, especially lean body mass, by ensuring an adequate intake of energy, carbohydrate, protein, vitamins, and minerals. In considering the nature of the ration, continued effort to improve flavor, texture, and other organoleptic qualities should be pursued. The CMNR believes that current rations are of very high quality given what they are designed to do. Efforts to provide enhancements that will alter the flavor of entree items through the use of seasonings and other condiments should receive continued research and development. Use of newer processing technology should also be integrated into current rations to preserve greater texture of thermostabilized foods, which are packaged in flexible containers. Finally, research should be continued to provide greater stabilization of fat within other food components to reduce the appearance and mouth feel of greasiness in high-fat foods. Although the extent to which the eating situation can be changed may be limited, making specific time available for eating is important and perhaps critical. Ideally soldiers should be able to eat in groups, and the opportunity to interact and share experiences should be provided when the tactical situation permits. Steps should also be taken to cope with environmental factors that detract from food acceptance. For example, continued development of equipment for heating and preparing foods that can be used in remote locations and extreme environments, and improvement in individual equipment for preparing meals,

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations should be undertaken. With indication from existing military and commercial research that "nibbling" can play an important role in overall energy intake, consideration should be given to the development of additional ration components that can be readily stored in pockets and consumed at a later time, especially high calorie and nutrient rich beverages of high acceptability. Finally, steps should be taken to motivate soldiers to consume sufficient quantities of food to more nearly match their energy expenditures and maintain optimal performance. This motivation would be fostered by education and by encouragement through command leadership. The soldier should be provided information about the physiological and functional consequences of underconsumption of rations. Commanders should emphasize the quality of the food system and thereby create a positive image for the ration. The entire command structure should be involved in this effort. Special training on the importance of nutrition in maintaining physical and cognitive performance and morale should be provided to all command personnel. Platoon sergeants should be capable of informing their soldiers about their needs for adequate energy and water intake. The ultimate goal should be that ration consumption should be given equal priority to other training needs of the soldier. The image of the ration both for the civilian and the soldier should also be improved. Current new endeavors incorporating humor with a nutrition and performance message into films appear to be a positive step if the impact of these films is carefully measured and the education message is retained. Changing the labeling of the individual food items will also be helpful. More information about the nutrient content and on alternative means of preparation of the entree should be included. Although outer packaging may have to comply with camouflage requirements, more colorful labeling of internal packaging would provide greater product appeal and relief from monotony. 5. What further research needs to be done in these areas? This question will be addressed in the last section of this chapter, Areas for Future Research. CONCLUSIONS The Underconsumption Problem Studies of field training exercises typically report underconsumption of military operational rations. Underconsumption in this context has been defined as an energy intake insufficient to meet the needs of the energy expenditure. The consequence is weight loss, with the amount of the weight loss being proportional to the underconsumption of energy from the ration. In six studies

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations where the doubly labeled water method was used to measure energy expenditure, the Meal, Ready-to-Eat (MRE) intakes were compared with other ration combinations during field training exercises lasting from 10 to 30 days. An average underconsumption of approximately 1,552 kcal/d (range 520-2,199 kcal/d) relative to measured energy expenditure was demonstrated. All but one of these studies were conducted under conditions known to markedly increase energy requirements (BMR elevated 20–40 percent) and have shown energy consumption ranging from 52 to 85 percent of energy expenditure. In a series of short-term studies with research modifications of the MRE ration, there has been improved energy intake with each MRE version (for example, MRE IV and MRE improved, MRE VIII and supplement, etc.). However, it is not known if this increase is sustained over longer-term use in the field or represents a novelty effect. Both consumer and military research has indicated that some ration components such as bread, high-starch vegetables, and certain beverages can be expected to retain their high acceptance. In contrast, limited studies using A Rations or mixed rations in field settings have shown energy intakes approximating energy expenditure (cf., Rose and Carlson, 1986). Therefore, it appears that under certain conditions, consumption of rations in the field can equal energy expenditure. It should be recognized that a comparison of field exercises that provide A Rations, which consist of hot and/or fresh foods, with those that supply only MREs represent measurement of ration acceptance confounded with other variables. Factors other than ration quality or food acceptance including food temperature and variety, as well as situational factors and logistics, can have a major impact on consumption of military operational rations. Potential Effects of Underconsumption on Performance The significance of underconsumption, with its consequent loss in body weight, is its impact on physical and cognitive performance. The MRE studies show that while daily energy deficits of 1,000 to 1,500 kcal/d occurred, protein and other major nutrient intakes remained at basically adequate levels. Thus, during periods of from 30 to 42 days, deficiencies of nutrients other than energy are unlikely when consuming the MRE ration. The rate of weight loss must be considered in addressing the potential impacts of underconsumption on performance. In physically fit and healthy troops rapid weight loss of 3 to 5 percent in less than 48 hours is primarily due to dehydration and can impact on physical and cognitive performance. Weight loss in excess of 5 percent in this time frame will most likely be associated with decreased performance and can lead to negative effects on health. In initially well-nourished and properly hydrated troops, weight losses not associated with trauma or disease reflect the deficit in energy intake relative

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations to expenditure. Therefore rapid weight loss (in excess of 2 lb/wk) indicates significant underconsumption of energy (1,000 or more kcal/d). A loss of 10 percent of body weight in a soldier of initial weight of 160 lb in just 4 weeks reflects a kcal deficit in the range of 2,000 kcal/d. If weight losses are modest in the range of 1 lb/wk the loss will primarily be from body fat. More rapid losses, particularly in lean individuals, will reflect a greater loss of lean body mass in addition to body fat. Weight losses primarily from body fat are not likely to reduce performance; however, as weight losses increase and an increasing percent of the loss is from muscle tissue, measured decreases in performance will occur as shown in the studies reported by Friedl (see Chapter 14 in this volume). Soldiers with lower body fat will more lean muscle mass from the beginning than those with higher fat reserves (Vanderveen et al., 1977). Given the individual variation in body composition of physically fit soldiers, it is not possible to specifically relate potential performance deficit to a specific percent loss of body weight, particularly in a period of 4 to 6 weeks. The problem is further complicated by the possibility of an individual, who may have lost 5 to 10 percent of body weight in a deployment, being redeployed before sufficient time to regain the lost weight. The individual will face a further weight loss with lower fat reserves and consequently lose lean body mass with even a relatively small loss of body weight. Therefore it seems prudent to minimize body weight losses when possible during operations to maintain a high degree of fitness and performance. This may be particularly important in the current downsizing of the forces as units may be frequently deployed as the need arises in various parts of the world. Very limited data are available on the impact of weight losses on cognitive performance. Closely related are potential mood or morale changes that may adversely affect cognitive performance. Therefore, careful attention to the weight changes in a unit during extended operational deployment is important to assure that operational capability is maintained. Strategies to Overcome Underconsumption Underconsumption of military operational rations is undoubtedly a multifaceted problem: Ration factors, such as ration image, palatability of individual components, nutrient density, variety, meal and meal item appropriateness for the time of day, and fluid intake, contribute to the general level of acceptance. Situational factors, such as eating location, social setting, and allowing sufficient time to eat and drink during deployment and in the field, as well as appropriate meal scheduling with consideration of changes in circadian rhythms, are likely to be important.

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations Environmental factors, such as protection from heat or cold, ability to heat entree components or consume fluid products at appropriate temperatures, and the accessibility of fluids, influence food intake. Emotional state, such as feelings of security from enemy action, can affect appetite and ingestive behavior. Leadership issues, such as influence of the unit commander on soldier attitudes toward ration consumption, can be critical. Positive attitudes expressed by officers and noncommissioned officers can influence intake. Commanders may be influenced by effects of ration intake on morale and/or on physical and cognitive performance over a period of time. A subset of the leadership issue is individual soldier attitude. An important step in developing strategies to overcome underconsumption of military operational rations is to analyze critically the available data. Such analysis should help identify the potential contribution of the factors outlined above to the underconsumption issue. This analysis will serve two important purposes. First, those factors relating to ration, situation, environment, and leadership that appear to bear the greatest impact within each category could be identified and quantified to the extent possible. Then a field feeding doctrine could be developed in which each of these major factors is quantified, enabling field commanders to make informed choices relative to the situations in the military operation. Significant efforts on the part of the U.S. Army Natick Research, Development and Engineering Center (NRDEC) to improve the acceptability of rations, particularly the MRE, have resulted in a demonstrated improvement in intake in experimental field settings. The MRE has great flexibility in its pattern of use; for example, it can be eaten by the individual soldier while on the move, in isolation, and without heating. This scenario will likely result in the least favorable consumption of the ration. However, if the combat situation permits, combat units (squad, platoon, and companies) could be permitted to come together at a scheduled time to consume their MREs in a more favorable social and environmental situation. Given this context, MRE consumption is likely to be higher than when eaten in isolation, and the troops will remain in a potentially better nutritional condition for forthcoming operations. Second, constructing a ration consumption model in which the incremental effects of the various factors that may influence intake relative to need are identified and quantified would help to delineate the state of current scientific knowledge. Gaps that exist (presumably with an indication of the relative importance of each to facilitate setting research priorities) could be identified and a research agenda developed. Information gleaned from this model would be an important step in developing a field feeding doctrine. The development of the new concept in the Army Field Feeding System as outlined by Peter Motrynczuk in Chapter 4 would reduce the long-term dependence on the MRE and, at least in theory, overcome some of the

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations concerns over the weight losses due to underconsumption observed in the field studies. The highly engineered MRE system has functioned very well in fulfilling the original concept of a highly portable, nutritionally adequate ration for use in the initial stages of a military operation. The decision by senior Army leadership to implement this new field feeding system will allow the availability of hot, prepared meals of more traditional foods when appropriate for the tactical situation. Not only will the rations be more similar to traditional foods, but the eating environment will often be more conducive to greater food intake. Current food technology, packaging, and distribution technology, coupled with efficiently engineered preparation and distribution, should give the combat soldier more acceptable rations in most environments. Moving in the direction of supplying hot meals whenever possible, including in the field, is an important strategy for overcoming underconsumption and improving morale. However, the MRE may still be used in initial combat operations for varying periods of time to a maximum of 21 days (U.S. Department of the Army, 1995), and data of the type suggested above would be valuable during that initial period. In addition, there are likely to be situations where operational and logistical constraints may require extended use of MREs or related systems. Therefore it seems useful to evaluate those factors that may optimize the MRE system to better meet the nutritional needs of the soldier under these potentially adverse conditions. RECOMMENDATIONS 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. 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. Suggested criteria for assessing whether energy consumption is adequate to meet energy expenditures for individual soldiers are provided in Table 2-1. Moreover, as suggested by Schnakenberg (see Chapter 6 in this volume) the appropriate criterion to evaluate whether troops are eating enough of their ration to meet their energy demands should be that the average body weight loss of the test unit does not exceed 3 percent of initial body weight over a period of several weeks. While underconsumption of operational rations in the training environment is not likely to result in significant reduction in physical or cognitive performance,

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations TABLE 2-1 Likely Causes of Weight Loss and Potential Impact on Performance* Average Body Weight Loss Time Period Likely Cause Potential Performance Impact <3% 24 hours Inadequate fluid intake Unlikely   24 hours-4 days Energy deficit Unlikely >3%<10% Less than 48 hours Principally inadequate fluid intake Highly likely, particularly cognitive deficits   3 days-4 weeks Energy deficit Unlikely >10% Less than 48 hours Inadequate fluid intake Serious deficits   3 days-12 weeks Severe energy deficit Very likely   12 weeks or more Energy deficit Unlikely * The performance deficits shown in this table will be influenced by (a) the initial body composition of the individual; (b) the speed of weight loss; (c) the composition of the loss (i.e., water and electrolytes, lean body mass, and fat); (d) the presence of trauma, infection, or illness; and (e) the tests being used to measure performance decrements. 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. Since there is evidence that the provision of A or B type rations in training environments does more nearly match energy intake with energy expenditure, it seems important to evaluate the new Army Field Feeding System under operational training environment as early as possible. If this system succeeds in minimizing underconsumption during these training exercises, the focus of research on MREs, T Rations, and other operational rations could be related to evaluating factors that in the short term (3–21 days) may enhance ration consumption or enhance performance in stressful environments. The Committee on Military Nutrition Research also recommends: Even short term deprivation of food intake can lead to performance deficits due to the unpredictable stress of field training, combat situation, hypohydration, and environmental extremes. Every effort should be made to keep soldiers well hydrated to avoid hypohydration-induced anorexia. The goal should be to have individual energy intakes match energy expenditures and thereby provide sufficient food in a manner that encourages soldiers to meet their needs. A field feeding doctrine analogous to the highly successful water doctrine, which highlights that food is the fuel of the soldier, should be considered. Such a doctrine will provide guidance to military commanders. In the doctrine an outline of factors that will tend to reduce ration consumption and possible steps to correct these conditions can be useful in helping to ensure that top-notch performance is maintained.

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations Because the MRE will continue to be the ration used initially in most military operations, continuing effort should be made to enhance its consumption. Recommended changes include improved individual items including the addition of carry-away snack items, greater variety and enhancements to reduce monotony, improved packaging, better labeling, and creative marketing/training in the importance of the ration and its use. Unit commanders should be informed of the potential consequences of weight loss due to dehydration as indicated by a rapid weight loss (2–5 percent in 24–48 hours) or the longer-term effects of underconsumption of rations and should monitor their units to ensure this underconsumption does not adversely affect performance especially during combat. Whenever possible, monitoring should include periodic body weight measurements and other simple anthropometric measures feasible in the field. As a minimum, body weight measures should be done routinely as part of deployment and return activities. Weight losses in the range of 10 percent in operations extending over 4 weeks raise the concern of reduced physical and cognitive performance and have possible health consequences in some of the individuals in the unit. Since data indicate that the addition of fruit-flavored drinks and flavored shakes with caloric sweeteners to more recent versions of the MRE has led to increases in total energy intake, the CMNR recommends that these items continue to be included in the overall menu program. Further, substitution of existing beverages with artificially-sweetened products may prove counterproductive. Unit commanders should be provided guidance as to ways of minimizing the adverse effects of the field environment (e.g., inclement weather, unappetizing local conditions, and lack of congregate meal times) on consumption where possible. This training would improve ration consumption and thus help to minimize performance decrements. The impact of inadequate fluid and food on physiologic function and performance should be emphasized to commanders in light of their importance as role models for increasing soldier food intake. Foods provided as snacks can be an important source of energy and other nutrients. Such foods could be provided as part of the MRE or as additional food items. A guide should be prepared for commanders in which the impact of various factors involved in food consumption and performance is summarized, based on currently available data. Unit commanders can use such a guide to assist them in making informed decisions concerning the need to improve feeding scenarios during military operations. Such a guide could indicate when changes were needed to avoid possible decrements in unit performance.

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations Continued efforts in the development of promotional materials to improve the image of military operational rations, such as the films shown at the workshop, are encouraged. Tied to this effort should be a careful research plan that measures the impact of these materials on soldiers' attitudes. 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. 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 Committee on Military Nutrition Research recognizes the concern that the loss of weight by personnel during training and operations poses to the military. The scientists at the U.S. Army Research Institute of Environmental Medicine (USARIEM) and U.S. Army Natick Research, Development and Engineering Center (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 following are suggested by the CMNR as future areas for study that would build on this excellent research base: Follow-up interviews with soldiers who participated in Operation Desert Storm that include direct questions about weight loss, food intake, and appetite as well as questions about food items and situational factors would be an important step in interpretation of experimental data. For example, did you lose weight? How much weight? Were you overweight at the start? Why do you think you lost weight? How did you feel about the weight loss? Did you want to lose weight? More data on food acceptability under actual rather than simulated field conditions should be collected. This data collection should include both rating scales as well as actual consumption data. Focus group research should be carried out with current troops, including women, and with combat veterans with questions directed toward feeding systems in the field including the questions related to MRE packaging, menu items, criticisms, and suggestions for improvement.

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations Practical measures should be created to develop, test, and refine a ''field feeding doctrine" as described earlier in this report. The food doctrine would be analogous to the successful water doctrine currently in use. A simple system should be developed and field tested to monitor body weight and body composition of troops before and after deployment. This system could be used in all field conditions including combat operational training. Additional field studies should be conducted that monitor energy intake and energy expenditure using doubly labeled water measurement techniques in temperate and hot environments for comparison with the six existing studies conducted in cold and high-altitude environments. Body composition measures would also be desirable if simple methods were used. The relationship between hydration and food intake in military field settings bears additional, carefully designed research. The committee believes the existing research on food intake, performance, food item preference, and eating situational factors would first of all benefit from a thorough, careful cross-study integration and interpretation. A multifactorial computerized research model that incorporates the most pertinent findings should then be compiled. This model can be used to assist with the generation of specific hypotheses for future studies, and may be used for selected meta analysis where appropriate. Identification of critical and appropriate physical and cognitive tasks, and careful measurement of performance during field operations or recruit training when weight loss is anticipated, would assist in further quantifying the relationship between underconsumption and performance. Future field studies should address the question of MRE food item wastage as it relates to specific nutrient intake in relation to energy intake and expenditure. The influence of menu variety on intake needs to be tested over a period of time. Carefully designed menu rotation studies that incorporate current understanding of the impact of variety, sensory specific satiety, temporal habituation patterns, energy density, the fat and fiber content of foods, and palatability on intake and body weight could provide directly relevant information. A brief study that systematically administered ibuprofen to troops in field exercises could provide information on a potential generalized stress/cytokine/food intake mechanism. All future research studies and focus groups should include women and combat veterans where feasible. The committee 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

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Not Eating Enough: Overcoming Underconsumption of Military Operational Rations requires follow-up evaluation as to its effectiveness and ways it can be improved. The CMNR believes that the military services, through their pool of volunteer personnel, offer an excellent and often unique opportunity to generate research data and statistics on the nutrition, health, and stress reduction in service personnel. These findings can be directly applied to improving both the health and the performance of military personnel and those of the general U.S. population. The Committee on Military Nutrition Research is pleased to participate with the Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, U.S. Army Medical Research and Development Command, in programs related to the nutrition and health of U.S. military personnel. The CMNR hopes that this information will be useful to the U.S. Department of Defense in developing programs that continue to improve the lifetime health and well-being of service personnel. REFERENCES Rose, M.S., and D.E. Carlson 1986. Effects of A Ration meals on body weight during sustained field operations. Technical Report 2–87. Natick, Mass.: U.S. Army Research Institute of Environmental Medicine. U.S. Department of the Army 1995. Revised policy on sole source consumption of Meal, Ready-to-Eat (MRE). June 21. Washington, D.C. Vanderveen, J.E., T.H. Allen, G.F. Gee, and R.E. Chapin 1977. Importance of body fat burden on composition of loss in body mass of men [abstract]. Second International Congress on Obesity, October 23–26, Washington, D.C.