['This study assessed if walking at a self-selected pace could improve postprandial glucose and insulin concentrations in obese adolescents consuming high-fructose (HF) or high-glucose (HG) diets.', 'Seven obese male and female adolescents (18 ± 1 yr) performed 4, 15-day trials in a random order, including 1) HF-diet (50 g fructose/d added to normal diet) while being sedentary, 2) HG-diet (50 g glucose/d) while sedentary, 3) HF-diet with additional walking, and 4) HG-diet with additional walking. On the 15th day of each trial, the participants performed mixed meal testing in the laboratory in which they consumed three liquid shakes (either HF or HG) and during the HF and HG sedentary trials, the participants took < 4000 steps while in the laboratory but during the walking trials took ≥ 13,000 steps during testing.', 'Walking did not alter postprandial glucose concentrations. Although walking reduced insulin secretion by 34% and 25% during the HF- and HG-diet, respectively (P < .05), total insulin concentrations were only significantly reduced (P > .05) with walking during the HF trial, possibly because walking enhanced insulin clearance to a greater extent during the HF-diet.'] Does walking reduce Postprandial Insulin Secretion in Obese Adolescents Consuming a High-Fructose or High-Glucose Diet?