Short-term dietary energy restriction reduces lean body mass but not performance in physically active men and women.

We studied the effect of moderate, short-term energy restriction on physical performance in physically fit men (n = 13) and women (n = 11) in a controlled clinical research setting with a metabolic kitchen, exercise testing laboratory and training facility. The experiment consisted of a 10 d baseline period followed by either 2 wk of dietary energy restriction (750 kcal/d; n = 16) or energy balance (control; n = 8). During this 24 day study, exercise energy expenditure averaged 465 +/- 5.7 kcal/d in all subjects and was accomplished through treadmill running at a self-selected pace. Body weight was maintained in the control group (-0.36 +/- 0.24kg), but energy restriction resulted in weight loss of -1.29 +/- 0.16 kg (p < 0.001). There was a trend for lean body mass to decline more in the energy restriction group (p = 0.093), accounting for 61% of the weight loss, and urinary nitrogen excretion also tended to be higher in the energy restriction vs. control group (i.e., 13.2 +/- 1.1 vs. 11.2 +/- 1.0g/d; p = 0.089). Muscle strength (leg & shoulder press; 1 repetition maximum) was maintained or increased during the energy restriction period. Muscle endurance, assessed by leg squats to fatigue, and 5 mile run time improved following two weeks of energy restriction or balance. Anaerobic capacity (Wingate Test) increased slightly in the restriction (+ 368 +/- 219 joules) but declined in the control group 649 +/- 288 joules; p<0.05). We conclude that short-term (2 weeks) moderate energy restriction (approximately 750 kcal/d) results in weight loss but does not impair performance in physically fit young men and women.

Incorporating new recipes into the Armed Forces Recipe File: determination of acceptability.

As part of a project of decrease fat, cholesterol, and sodium in soldiers' diets, new ethnic and breakfast items were developed and standardized for 100 portions. Acceptability data were collected after initial recipe development, during recipe validation at a collaborating university, and in an actual Army garrison. Acceptability was determined using a nine-point hedonic scale; products rating > or = 6.0 in initial tests were prepared in garrison. Acceptability data were compared among test settings, ethnic categories, and food type. When grouped by ethnic categories, acceptability ratings varied more than when grouped by food type. Ratings varied most between development and validation settings (7.2 vs. 6.6; p < 0.05) and least between validation and actual Army settings (6.6 vs. 6.6; not significant). Because acceptability ratings were similar between the validation site and the Army garrison, future recipe development may continue without additional testing at actual Army garrisons, leading to more timely armed forces recipe file additions.

Nutrient intakes and characteristics of normal weight, female military personnel consuming foods reduced in fat or energy content.

The nutritional implications of consuming reduced fat or reduced energy foods (RED) were examined in 50 women who were participating in a larger study of iron status while enrolled in the U.S. Army Medical Department Officer Basic Course. The subjects recorded their food intake for a 7-day period. Reduced fat or reduced energy foods were identified as foods labeled "reduced-calorie, reduced-fat, diet, or low-calorie". The women were divided into two groups, those eating > 14 RED per week (N = 28) and those eating < or = 14 RED (N = 22). The > 14 RED group tended to be Caucasian, single, had a lower body mass index (21.2 vs. 22.5), and exercised more. The mean daily intake of the > 14 RED group was significantly higher in carbohydrate, dietary fiber, thiamin, riboflavin, niacin, vitamin B6, folacin, calcium, phosphorus, magnesium, iron, zinc, potassium, and sodium, and significantly lower in cholesterol. The percentage of energy from fat was significantly lower in the > 14 RED group than the < or = 14 RED group (p < 0.01). There was no significant difference in energy intake between the two groups. More women in the > 14 RED group used dietary supplements. The > 14 group consumed more dairy products and less sweetened beverages. These results demonstrate that the consumption of reduced fat or energy foods did not have a significant impact on total energy intake in these normal weight women. Individuals consuming these foods may subsequently consume less energy from fat and improve the nutrient composition of their diet by selecting healthier food choices.

Influence of a carbohydrate drink on nutritional status, body composition and mood during desert training.

BACKGROUND: Nutritional intake by military personnel is typically inadequate during field exercises, potentially compromising health and performance. HYPOTHESIS: Drinking a supplemental carbohydrate (CHO) beverage will increase total caloric intake and maintain nutritional status during military training in the desert. METHODS: A total of 63 volunteers were randomly assigned to one of two groups to receive either a CHO or placebo beverage with military rations during an 11-d desert field exercise. Fluid intake was ad libitum and adequate rations were provided. Blood samples were collected twice to assess nutritional status, and nutrient intake was determined with consumption data. Mood state was examined by questionnaire. RESULTS: Energy intake was significantly higher in the CHO group (3050 kcal x d(-1) vs. 2631 kcal x d(-1)), with additional CHO from the beverage providing energy with some compensation by reduced fat and protein intake. Intakes of energy, folacin, calcium, magnesium, iron, and zinc in both groups were inadequate, with intakes significantly lower (p<0.05) for calcium, magnesium, and zinc in the CHO beverage group. Blood parameters of nutritional status remained within normal ranges with no differences between groups, but significant decreases were seen in pre-albumin. No changes in mood were seen during the training, nor after exposure to desert conditions. CONCLUSIONS: The operational ration supplemented with a CHO beverage significantly increases CHO and energy intakes compared with standard rations and maintains nutritional status for short exercises. Fortification with micronutrients most at risk for deficient intake from foods may be needed for longer deployments.

Stress fractures in female army recruits: implications of bone density, calcium intake, and exercise.

OBJECTIVE: To identify characteristics and factors associated with increased risk for stress fractures in military women. DESIGN: Case-control study to retrospectively examine physical activity, prior calcium intake, and bone density as predictors of stress fractures. SETTING: A military training installation which incorporates physical training for women. SUBJECTS: Forty-nine female soldiers with confirmed stress fractures (cases) and 78 female soldiers with no orthopedic injuries (controls), aged 18 to 33 years. MEASURES: Retrospective self-reports of habitual exercise, sports participation, and food intake; current height, weight, and body mass index (BMI); demographic variables (age, ethnicity, menstrual patterns, smoking habits); and bone density on radiologically defined stress fractures. RESULTS: Cases and controls were similar in height, weight, and BMI. Measurements of bone density (g/cm2) at the trochanter (cases, 0.77+/-0.09; controls, 0.77+/-0.08); femoral neck (cases, 0.94+/-0.10; controls, 0.94+/-0.09); Ward's triangle (cases, 0.91+/-0.11; controls, 0.93+/-0.11); lumbar spine (cases, 1.21+/-0.12; controls, 1.24+/-0.10); and radius shaft (cases, 0.67+/-0.09; controls, 0.68+/-0.05) were not different between groups. Calcium intake was not different between groups (cases, 1154+/-751 mg/day; controls, 944+/-513 mg/day) and did not correlate with bone density (r=0.01 to -0.06 at four sites). Sports participation positively correlated with bone density in the hip (r=0.49). Leisure activity energy expenditure (kcal/day) tended toward association with lower stress fracture risk as expenditure level increased (p=0.06). CONCLUSION: Stress fracture in female Army recruits was not correlated with bone density or calcium intake during adolescence, although a weak relationship to prior physical activity was observed.

Fruit and vegetables in the service member's diet: data from military institutional feeding studies.

Previous surveys of the U.S. population have indicated that typical intakes of fruits and vegetables are substantially below recommended levels. Using data from nine dietary studies, we examined 798 service members who subsisted in government-run feeding programs to determine how they differ from the general population. The findings of this retrospective investigation showed that an estimated 43% of service members met the minimum recommendation of five daily servings of fruit and vegetables compared with 6% of the general population. Among genders, more males had fruits and vegetables rich in carotenoids (22 vs. 10%), whereas a slightly higher proportion of females consumed cruciferous vegetables (14 vs. 11%). Only 3% consumed no servings of vegetables, and 11% consumed no servings of fruits. Intake in overall quantity of fruits and vegetables was higher among service members, but further efforts are needed to increase consumption of cruciferous vegetables and fruits and vegetables rich in carotenoids.