Committee on Military Nutrition Research: Activity Report 1992-1994 (1994)

Since 1982 the Army has field tested and the CMNR has reviewed a number of studies conducted by the Army of soldier intake of operational rations in various environmental conditions. Across these studies the Army scientific staff noted recurring underconsumption of the study ration in that soldiers did not consume sufficient calories to meet energy expenditure and consequently lost body weight. The caloric deficit has consistently been in the range of 700–1,000 kcal per day and thus raises concern about the influence of such a deficit on physical and cognitive performance, particularly over a period of extended use. Other studies involving special purpose operational rations supplying limited energy (1,500–2,000 kcal), but based on similar design of the Meal, Ready-To-Eat (MRE), were usually fully consumed and weight losses were experienced as would be predicted by the limited calories in the rations. Additionally, anecdotal reports from Operation Desert Storm indicated that some units may have used MREs as their sole source of food for 50 to 60 days—far longer than the original intent when the MRE was initially field tested.

Surprisingly, hedonic ratings of the ration items in field studies have been usually quite positive, in spite of the actual intakes. Successive modifications of the MRE have produced small improvements in total consumption but have not affected the major caloric deficit.

The Committee on Military Nutrition Research (CMNR) of the Food and Nutrition Board (FNB) was asked to assist a collaborative program between scientists in the Division of Military Nutrition, U.S. Army Research Institute of Environmental Medicine (USARIEM), and the U.S. Army Natick Research, Development and Engineering Center (NRDEC), to strategize on how to overcome underconsumption of military operational rations. An underlying question to be reviewed was whether this was an expected and perhaps preventive situation in combat settings. The CMNR was requested to hold a workshop to review the relevant literature, hear the most current research findings from within the Army related to these issues, and consider assessments of this issue from experts in related fields. The workshop was developed to thus focus on the various factors that may contribute to the reduced intake of operational rations, the potential effect on soldier performance, and suggest steps that may be taken to overcome the problem.

A small planning group was given the task of identifying the pertinent topics and the participants. This task force, comprised of representatives from USARIEM, Natick Laboratories, and the CMNR, met at USARIEM on April 30, 1993, to plan the workshop. The task force developed five questions to be addressed at the workshop:

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

2. What factors influence underconsumption in field operations? Identify the relative importance of:

   • Rations

   • Environment

   • Eating situation

   • The individual

3. At what level of underconsumption is there a negative impact on physical or cognitive performance? What can be done to overcome this degradation?

4. What steps are suggested to enhance ration consumption within the environment of military operations? Similarly, what can be done to overcome deficits in food intake?

5. What further research needs to be done in these areas?

The CMNR recognized that underconsumption of field rations is a complex issue that is related to an individualized response to the multiple stressors of a field training or operational setting. In the planning session with scientists from USARIEM and NRDEC, committee members voiced the need

to hear more specific information about (a) Army field feeding logistics; (b) new developments in operational rations; (c) an overview of Army research on food intake patterns and factors affecting food intake; (d) recent Army research results on the impact of lowered caloric intake on performance; and (e) expert reviews of physiological, psychological and social factors that influence eating. This information was incorporated into presentations from Army scientists and staff at the workshop.

The workshop was held November 3–4, 1993 at Natick, Massachusetts. This workshop included presentations from military and non-military scientists with expertise in food engineering, food marketing strategies, food science, nutrition, nutritional biochemistry, physiology, psychology, and social factors. A panel discussion was held at the end of the workshop to summarize the findings and discuss potential strategies to increase ration intake. The four invited panelists brought additional expertise in food development, complex data analysis, nutrition education, and ingestive behavior. The invited speakers were chosen for their specific expertise in the areas related to the meeting topic and were requested to present in-depth reviews of their area of expertise as it directly applied to the five questions and to include their own recommendations on the issues. Speakers subsequently submitted written versions of their presentations. Committee members later reviewed the workshop presentations and drew on their own expertise and the scientific literature to develop their summary, conclusions, and recommendations. The summary and recommendations of the CMNR will be reviewed by the FNB and an anonymous panel of peers according to National Research Council policy.

The conclusions and recommendations of the Committee on Military Nutrition Research will be submitted to the U.S. Army Medical Research, Development, Acquisition, and Logistics Command (Provisional) [USAMR-DALC (PROV)] as part of the workshop report, Not Eating Enough, Strategies to Overcome Underconsumption of Operational Rations in early 1995. The proceedings of this workshop will be published and disseminated using the workshop format in the CMNR series style. This study has thus originated from concern within the military about the consistency of the deficit in caloric intake and whether such a decrement could lead to important reductions in physical and/or cognitive performance of troops in military operations. The report will focus on the various factors that may contribute to the reduced intake of operational rations, the potential effect on soldier performance, and suggest steps that may be taken to overcome the problem.