ABSTRACT

The effect of varying energy intakes on nitrogen balance was investigated in thirteen young women aged between 21 and 32 years. The subjects were fed a previously determined minimum requirement of protein (0.47 g/kg) at two levels of dietary energy, high energy intake at 48.4±3.70 kcal/kg bodyweight and low energy intake of 33.8±2.86 kcal/kg bodyweight (about 20% above and below the estimated energy requirement based on their energy expenditure); Nitrogen balance was determined from the nitrogen in food, urine, feces and sweat. Nitrogen balance was -8.6±5.44 mgN/kg with the low energy intake and increased to +10.82±6.35 mgN/kg with the high energy intake. Regression analysis, showed that all subjects maintained zero nitrogen balance with an average energy intake of 40±0.94 kcal/kg/day. Variation in energy intake also altered the net protein utilization of the habitual diet in till subjects by 1.0 to 3.5 units/kcal per kg body weight. Energy requirement was estimated on lite basis of constant body weight and the nitrogen balance. Body weight was maintained constant at an energy intake of 40.8±4.21 kcal/kg body weight