Effects of an eight-month weight-control program on body composition and lipid oxidation rate during exercise in obese children

Objective: To investigate the effects of an 8-month multidisciplinary weight-control program, including 2 h/week of moderate physical activity, nutritional education lessons and psychological follow-up, on body composition and lipid oxidation rate during exercise in obese children. Design: Nineteen Q boys and 12 girls) obese children, aged 8-12 yr [mean body mass index (BMI) z-score: 2.3 and fat mass: 35.8%] participated in this study. Before and at the end of the weight-control period body composition was assessed by bioelectrical impedance, lipid oxidation rate by indirect calorimetry during a graded exercise test, and time devoted to various activities and energy intake in free-living conditions by questionnaire. Results: All children completed the study, at the end of which BMI decreased significantly by mean 0.6 +/- 0.5 and 0.5 +/- 0.8 kg/m(2), in boys and girls, respectively (p < 0.05), and fat mass (FM) decreased by 1.7 +/- 2.8 and 1.4 +/- 1.3 kg in boys and girls, respectively (p < 0.05). In addition, lipid oxidation rate during exercise increased significantly throughout the graded exercise test up to 21% at maximal lipid oxidation rate which happened at 48 +/- 5% of maximal oxygen uptake (VO(2)max), corresponding to 64 +/- 5% of maximal heart rate. Time spent at sedentary and very light physical activities decreased (p < 0.001) to the benefit of recreational activities at home. Conclusions: Multidisciplinary weight-control program, with moderate-intensity physical activities, induced decreases in FM without decreases in free FM, increases in VO(2)max, lipid oxidation rate during exercise, and time devoted to recreational activities in free-living conditions.