Energy requirements in response to high protein feeding in young male adults

Two experiments were conducted to investigate the effects of moderate (MPI) and high (HPI) levels of protein intake on energy utilization in 12 healthy young male adults who were confined to a metabolic unit for 56 days. The amount of energy supplied was adjusted so that the subjects could maintain a relatively constant body weight, which was used as the criterion to see whether the body was under an energy balance. All foods were supplied in conventional style. In the first experiment, six young men were given a diet of 1.18 g (MPI) and 1.74 g (HPI) protein/kg of body weight/day in consecutive periods. In the second experiment, another six young men were studied at a protein intake of 1.08 g (MPI) and 2.00 g (HPI)/kg/day. The results indicate that both energy intake and energy expenditure are independent of protein intake. The average gross energy intake of the subjects was between 2,300 to 3,240 kcal/day, corresponding to a light-to-moderate grade of energy expenditure. The efficiency of energy utilization did not differ significantly between the moderate and high levels of protein intake in adults.