Zello, Gordon A.Chilibeck, Philip D.2007-08-232013-01-042008-08-242013-01-04200720072007http://hdl.handle.net/10388/etd-08232007-155820The glycemic index (GI) of a pre-exercise meal has been shown to affect substrate oxidation during exercise and may influence exercise performance. Previous research in this area has focused on continuous, moderate intensity exercise. The purpose of this study was to examine the effects of low and high glycemic index (GI) pre-exercise meals on metabolism and performance during soccer-specific intermittent exercise. Thirteen trained male soccer players (22.3 ± 3.3 yrs) participated in four experimental trials in a repeated crossover design. Isocaloric low GI-high protein (lentils), high GI-high protein (potato + egg whites), or high GI-low protein (potato) meals were consumed two hours before a 90-minute treadmill soccer match simulation. A fasted control condition was also employed. Blood and expired gas samples were collected before and during exercise to assess markers of carbohydrate and fat metabolism. The distance covered on five 1-minute sprints (separated by 2.5 minutes of recovery) performed during the last 15 minutes of the match was used to assess performance. Serum insulin concentration at the start of exercise was higher in the high GI-low protein condition compared to all other conditions (pen-UScarbohydrateproteinexercise performancepre-exercise mealsGIsport nutritiontext