Resting metabolic rate in six- to ten-year-old obese and nonobese children.

The resting metabolic rate (RMR) and body composition of 130 obese and nonobese prepubertal children, aged 6 to 10 years, were assessed by indirect calorimetry and skin-fold thickness, respectively. The mean (±SD) RMR was 4619 ± 449 kJ · day-1 (164 ± 31 kJ · kg body weight-1 · day-1) in the 62 boys and 4449 ± 520 kJ · day-1 (147 ± 32 kJ · kg body weight-1 · day-1) in the 68 girls. Fat-free mass was the best single predictor of RMR (R2 = 0.64; p < 0.001). Step-down multiple regression analysis, with independent variables such as age, gender, weight, and height, allowed several RMR predictive equations to be developed. An equation for boys is as follows: RMR (kJ · day-1) = 1287 + 28.6 · Weight(kg) + 23.6 · Height(cm) -69.1 · Age(yr) (R2 = 0.58; p < 0.001). An equation for girls is as follows: RMR (kJ · day-1 = 1552 + 35.8 · Weight (kg) + 15.6 · Height (cm) - 36.3 · Age (yr) (R2 = 0.69; p < 0.001). Comparison between the measured RMR and that predicted by currently used formulas showed that most of these equations tended to overestimate the RMR of both genders, especially in overweight children.