Resting metabolic rate and thermic effect of a meal in low-and adequate-energy intake male endurance athletes.

The resting metabolic rate (RMR) and thermic effect of a meal (TEM) were determined in 13 low-energy intake (LOW) and 11 adequate-energy intake (ADQ) male endurance athletes. The LOW athletes reported eating 1,490 kcal.day-1 less than the ADQ group, while the activity level of both groups was similar. Despite these differences, both groups had a similar fat-free mass (FFM) and had been weight stable for at least 2 years. The RMR was significantly lower (p < 0.05) in the LOW group compared to the values of the ADQ group (1.19 vs. 1.29 kcal.FFM-1.hr-1, respectively); this difference represents a lower resting expenditure of 158 kcal.day-1. No differences were found in TEM between the two groups. These results suggest that a lower RMR is one mechanism that contributes to weight maintenance in a group of low- versus adequate-energy intake male athletes.