Weight, food intake, and body composition: effects of exercise and of protein deficiency.

CREWS, EUGENE L. III, K. WILLIAM FUGE, LAWRENCE B. OSCAI, JOHN 0. HOLLOSZY, AND ROBERT E. SHANK. kt’eight, food intake, and body cornposition: effects of exercise and protein dejiciency. Am. J. Physiol. 216(2): 359-363. 1969.-The effects of exercise and of protein deficiency, both separately and together, on food intake, weight gain, and body composition were studied. Exercising animals gained less weight than free-eating sedentary controls as a result of both an increase in caloric expenditure and a decrease in food intake. Exercise resulted in a significant decrease in the percentage of the carcass composed of fat, with a proportional relative increase in lean body mass. Sedentary calorie-restricted animals had a higher fat content than exercising animals of the same weight, suggesting a specific fat-mobilizing effect of exercise. Growing rats eating a lowprotein diet (8y0 casein) were markedly stunted but otherwise appeared healthy. They had a greater capacity for prolonged running than the rats on the normal protein diet. Protein deficiency resulted in a decrease in the percentage of the carcass composed of fat and an increase in the proportion made up of water. Because of the small size of the protein-deficient animals, total amounts of all four body constituents were markedly decreased.