Ten healthy young men (age: 21.7 ± 1.5 y, body mass index: 20.9 ± 1.1 kg∙m_2, VO2max: 53.7 ± 3.7 mL∙kg_1∙min_1) completed 1 hr of brisk walking at 46% VO2max 2 hr after eating one of three isocaloric breakfasts: a low-GI breakfast not including fructose content (LGI), low-GI breakfast including fructose beverage (LGIF) and a high-GI breakfast (HGI). All breakfasts provided 1.0 g∙kg_1 body weight carbohydrates, and the calculated GI values for the three breakfasts were 41, 39, and 72, respectively. In the LGIF and HGI trials, approximately 25% of participants' energy was derived from either fructose or glucose beverage.