Effect of exercise and protein intake on energy expenditure in adolescents

In order to evaluate the influence of physical exercise and protein intake on Resting Metabolic Rate (RMR) and Postprandial Energy Expenditure (PEE), 16 healthy, normal-weight, 15 year-old, adolescent males at the same stage of pubertal development were studied. They were assigned to two dietary groups receiving the same energy intake (1.3 x by measured RMR) and different proportions of macronutrients (13% protein, 39% fat, 48% CHO in Group A; 30% protein, 32% fat, 38% CHO in Group B). An increase in postprandial energy expenditure, relative to basal, was observed in all individuals. The postprandial energy expenditure was higher in group B than in group A. Postprandial Post-exercise Thermogenesis (expressed as Kcal/3 h) was significantly higher in group B than group A (p < 0.05). Although the RMR on the test day was not different between the groups, the RMR on day 2 was significantly higher than on day 1 in group B (p < 0.01). In group B, the post-exercise RQ was significantly lower than the preexercise RQ (p < 0.01). It is concluded that in normal-weight-adolescents, a hyperproteic diet followed by moderately-intensive exercise induces increases in EE and decreases in RQ in the postprandial post-exercise period and is accompanied by increase in the RMR the following day.