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