(MND) so that the Committee on Military Nutrition Research can put the issue of underconsumption of rations into perspective and determine what interventions are warranted. Is there really a problem? If so, is underconsumption a problem of such magnitude as to threaten health or performance, or is the problem mainly one of degrading morale or wasting of food dollars?

MND conducts ration tests in the field, using troops in their usual environments while they perform their everyday military duties. Most ration studies are performed to assess the nutritional impact of a prototype or an improved version of an operational ration. Data have been collected mostly from men, ages 19 to 30 years. Mean body weights have ranged from 75 to 81 kg. Study durations have varied from 5 to 30 days, although most studies lasted 7 to 10 consecutive days. One major exception was the Combat Field Feeding System-Force Development Test and Experimentation (CFFS-FDTE) conducted in Hawaii in 1985, which recorded food intake on days 2, 3, 6, 7, 12, 13, 18, 19, 24, 25, 30, 31, 36, 37, 42, and 43 of a 44-d field exercise (USACDEC/USARIEM, 1986). In all of the other field studies summarized in this chapter, although the study duration varied, data was collected on consecutive days.

In studies when most food intake was obtained from military dining facilities or when hot meals were served in the field, the dietary intake data were usually collected by visual estimation. For this method, the test subject presented his or her tray to a data collector before sitting down to eat. The data collector recorded the food items and visually compared the portion sizes of foods on the subject's tray to a weighed standard of the same food. The data collectors were trained to estimate portion sizes to within 10 percent. After the meal, the test subject returned to the data collector, who recorded the quantity of food remaining on the tray. Foods consumed outside the dining facility were recorded by the subject on food records.

For studies of individual field rations, dietary intakes were also obtained by self-recorded food record. Cards that were precoded and printed with the menu items were provided to the subjects. The subject had only to circle the proportion of a serving consumed next to the appropriate menu item. There were separate prompts for recording canteens or cups of water. When it was important to determine water intake accurately, subjects were provided with graduated bottles or canteens to measure their fluid consumption. A food record is a reasonably accurate method of collecting food intake data because ration items are individually packaged, single serving-sized pouches or bars. When the test subjects were accessible, dietitians collected and reviewed the