ABSTRACT
Purpose This study examined the effect of pre-exercise low and high glycemic index (GI) carbohydrate (CHO) meals on running performance. Methods Eight endurance-trained male runners completed two trials that were separated by at least seven days in a counterbalanced design. Two hours before the run and after an overnight fast, each subject consumed an isocaloric meal containing either low (GI = 37, LGI) or high (GI = 77, HGI) GI CHO foods that provided 1.5 g CHO(kg -1 body mass in random order. Each trial consisted of a 21km performance run on a level treadmill. The subjects were required to run at 70% VO 2max during the first 5km of the run. They then completed the remaining 16km as fast as possible. Results All of the subjects achieved a faster performance time after the consumption of the LGI meal (LGI vs HGI: 98 7? 2 min vs 101 5?2 min, P