Weight Maintenance and Food Intake

Abstract

It was shown that weight maintenance can be achieved in rats over a wide range of caloric intakes. Regimens for this purpose are given by: c × NDpCals % = 624 ± 12 where C = caloric intake/day/kg^0.73 and NDpCals % = net dietary-protein Cals %. Two pigs were maintained at constant weight with diets providing, respectively, 243 and 1,180 Cal./day. After 40 days the regimens were reversed and body weight was maintained for a similar period. The difference in caloric intakes could not be accounted for by differences in digestibility, losses in the urine, storage of depot fat, nor physical activity. Differences in expired carbon dioxide showed that all the ingested food was being metabolized. It was concluded that food energy may be converted directly into heat. The implications of these observations were discussed in relation to the measurement of the specific dynamic action of proteins, the prescription of diets for weight control, and the allowances of protein and energy to meet requirements.