Background: The prevalence of overweight and obesity in Chinese children and adolescents was increasing during the past few decades. The goal of this study was to investigate the effects of after-school exercise with or without diet restriction on total and central obesity, fitness level, and metabolic profile in overweight Chinese adolescents.
Methods: A ten-week weight loss trial was performed using a 2 × 2 block design (exercise × diet). Ninety-three overweight adolescents (average age: (13.6 ± 0.7) years; body mass index (BMI): 22.4 - 34.1 kg/m(2)) were randomly assigned to four groups: 1) diet (D); 2) exercise (EX); 3) diet plus exercise (DEX); and 4) overweight control (C). Caloric intake recipes were enacted based on individual age and corresponding ideal body weight. One-hour after-school exercise was performed once per day, four days per week for ten weeks. Changes of anthropometry, body composition, aerobic fitness, and metabolic biomarkers were determined.
Results: Groups D, EX and DEX had a significant decrease in BMI (P < 0.01) after the intervention. The percentage of body and truncal fat, and waist circumference were independently reduced by exercise (P < 0.05 and P < 0.01), but not diet. The decrease in body fat percentage was positively related with the exercise compliance (r = 0.34, P = 0.01). Exercise decreased truncal fat percentage and waist circumference, suggesting a reduction of central adiposity, but did not significantly affect body weight and BMI. Exercise significantly reduced serum low-density lipoprotein cholesterol (P = 0.037), which was positively correlated with decreases of truncal fat percentage (r = 0.222, P = 0.048). No significant effects of interventions on insulin sensitivity, early insulin release index, and aerobic fitness were observed.
Conclusion: At least twice a week of one-hour after-school exercise significantly attenuated central adiposity and had a significant impact on lipid profiles in overweight Chinese adolescents.