Effects of an intensive short-term diet and exercise intervention: Comparison between normal-weight and obese children

Lifestyle intervention programs currently emphasize weight loss secondary to obesity as the primary determinant of phenotypic changes. We examined whether the effects of a short-term lifestyle intervention program differ in normal-weight versus overweight/obese children. Nineteen overweight/obese (O; BMI = 33.6 ± 1.9 kg/m²) and 14 normal-weight (N; BMI = 19.9 ± 1.5 kg/m²) children participated in a 2-wk program consisting of an ad libitum high-fiber, low-fat diet and daily exercise (2-2.5 h). Fasting serum samples were taken pre- and postintervention for determination of lipids, glucose homeostasis, inflammatory cytokines, and adipokines. Only the O group lost weight (3.9%) but remained overweight/obese (32.3 ± 1.9 kg/m²). Both groups exhibited significant intervention-induced decreases (P< 0.05) in serum insulin (N: 52.5% vs. O: 28.1%; between groups, P = 0.38), homeostatic model assessment for insulin resistance (N: 53.1% vs. O: 28.4%, P = 0.43), leptin (N: 69.3% vs. O: 44.1%, P = 0.10), amylin (N: 28.7% vs. O: 26.1%, P = 0.80), resistin (N: 40.0% vs. O: 35.1%, P = 0.99), plasminogen activator-inhibitor-1 (N: 30.8% vs. O: 25.6%, P = 0.59), IL-6 (N: 58.8% vs. O: 48.5%, P = 0.78), IL-8 (N: 46.0% vs. O: 42.2%, P = 0.49), and TNFα (N: 45.8% vs. O: 40.8%, P = 0.99). No associations between indices of weight change and phenotypic changes were noted. A short-term, intensive lifestyle modification program is effective in ameliorating metabolic risk factors in N and O children. These results suggest that obesity per se was not the primary driver of the phenotypes noted and that dietary intake and physical inactivity induce the phenotypic abnormalities. These data may have implications for the weight loss-independent management of cardiometabolic risk in pediatric populations.