Energy metabolism in relation to body composition and gender in adolescents.

OBJECTIVE To study the effect of body composition on average daily metabolic rate (ADMR) and basal metabolic rate (BMR) in adolescence, and to examine current BMR prediction equations. STUDY Dutch adolescents were pooled with previously reported American and British subjects (n = 90 overall). BMR and ADMR were analysed by multiple regression. RESULTS Fat-free mass, BMR, and ADMR were higher in the obese than in the non-obese group (mean (SD): 53.2 (10.7) kg, 8.35 (1.57) MJ/d, and 13.64 (2.78) MJ/d, compared with 41.0 (8.1) kg, 6.42 (0.94) MJ/d, and 11.16 (2.21) MJ/d, respectively). BMR remained higher when adjusted for fat-free mass, age, and sex. ADMR adjusted for BMR was similar in the two groups. WHO equations overestimated BMR in obese boys and underestimated BMR in non-obese boys. CONCLUSIONS BMR, but not activity, is increased in obese adolescents and in male adolescents. The WHO BMR equations for adults are recommended for obese adolescents.