There is virtually no information on the metabolic impact of dietary fructose intake in adolescents despite their high fructose consumption, particularly via sweetened beverages. To determine the short-term metabolic effects of dietary fructose intake in obese adolescents. Six volunteers (3 M/3 F; 15.2 +/- 0.5 yr; 35 +/- 2 kg/m2; 39 +/- 2% body fat) were studied twice following 7 d of isocaloric, isonitrogenous high carbohydrate (60% CHO; 25% fat) diets with fructose accounting for 6% and 24% of total energy intake, respectively (random order). Insulin sensitivity and secretion were analyzed by the stable labeled intravenous glucose tolerance test and glucose and lipid kinetics using GCMS. A fourfold increase in dietary fructose intake did not affect insulin sensitivity or secretion, glucose kinetics, lipolysis or glucose, insulin, C-peptide, triglycerides, HDL- and LDL-cholesterol concentrations. In the short term, when energy intake is constant, dietary fructose per se is not a contributor to insulin resistance and hypersecretion in obese adolescents.