A low resting metabolic rate in late childhood is associated with weight gain in adolescence

Background and Objectives. Lower total energy expenditure (TEE) and resting metabolic rate (RMR) are associated with greater weight gain in Native American adults. Whether these effects exist in childhood is unclear. We hypothesized that lower energy expenditure measured in childhood would predict greater relative change in body mass index (BMI) during adolescence. Methods. Measurements of height, weight, body composition, RMR and TEE were completed in 181 Native American children at exams done at age 5 and 10 years, with 126 children having biennial follow-up assessments of weight and height after age 10 years until age 20 years. TEE and RMR were adjusted for age, sex, height, fat mass and fat free mass. BMI-change was assessed using population specific and Center for Disease Control (CDC) BMI z-scores and change in the relative difference to the 95th BMI-centile. Results. Lower adjusted RMR at age 10 years was associated with greater increase in population-specific and CDC BMI z-scores, greater increase in the relative difference to the 95th BMI-centile and greater weight gain (all r ≤ −0.22, p ≤ 0.01). However, no association was found with adjusted RMR at age 5 years and with adjusted TEE and physical activity level assessed at age 5 or 10 years. Conclusions. Lower adjusted RMR at age 10 years predicted greater change in adolescent BMI z-score indicating that the effects of relatively low metabolic rate on future weight gain in this population may begin in late childhood.