Are There Inter-Individual Differences in Fat Mass and Percent Body Fat as a Result of Aerobic Exercise Training in Overweight and Obese Children and Adolescents? A Meta-Analytic Perspective

Background: Determine whether inter-individual response differences exist with respect to changes in fat mass and percent body fat as a result of aerobic exercise training in overweight and obese children and adolescents. Methods: Using the meta-analytic approach, randomized controlled trials that examined the effects of aerobic exercise training on fat mass and percent body fat in overweight and obese children and adolescents were included. Change outcome standard deviations for fat mass and percent body fat were used to calculate true inter-individual differences from each study. The inverse variance heterogeneity model was used to pool results. Results: Pooled changes for inter-individual response differences in fat mass (16 studies, 575 participants) were 0.9 kg (95% confidence interval [CI], -1.4 to 1.8 kg) while tau (tau) was 2.9. For percent body fat, inter-individual differences (27 studies, 1035 participants) were 0.6% (95% CI, -0.6% to 1.0%, tau = 0.7). The 95% prediction interval for true inter-individual responses in a future study was -4.9 to 5.5 kg for fat mass and -0.7% to 1.7% for percent body fat. The percent chance, that is, probability, of a clinically meaningful difference in variability was 47% for fat mass and 26% for percent body fat, both of which were considered as only possibly clinically important. Conclusions: There is a lack of convincing evidence to suggest that true inter-individual response differences exist with respect to aerobic exercise training and changes in fat mass and percent body fat in overweight and obese children and adolescents.