Effects of Preexercise Candy Bar Ingestion on Glycemic Response, Substrate Utilization, and Performance

in International Journal of Sport Nutrition and Exercise Metabolism
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This study examined the effects of preexercise candy bar ingestion on glycemic response, substrate utilization, and performance ie 8 trained male cyclists. The cyclists randomly ingested oee large milk chocolate bar (1CB), two large milk chocolate bars (2CB), or a placebo (P) 30 min prior to a 90-min cycle ride at 70% VO2max followed by a 33-W increase every 2 min until exhaustion (~10 min). Glucose decreased after 15 min of exercise but returned to preexercise values by 30 min of exercise. Glucose concentration for 2CB was significantly higher than for P and 1CB at exhaustion, Insulin concentration increased in response to ICB and 2CB and returned to preexercise values within 15 min of exercise. No significant differences were noted for free fatty acid (FFA) concentrations, Jactate concentrations, respiratory exchange ratio, total carbohydrate oxidation, or estimated fat and carbohydrate oxidation rates. Time to exhaustion was similar among the groups. The results suggest that the transient lowering of blood glucose observed with preexercise milk chocolate bar ingestion 30 min prior to exercise may not cause major metabolic perturbations that impair athletic performance in trained athletes performing moderately intense cycle exercise.

Alberici is now with Continental insurance, Cranbury, NJ 08570. Farrell is with the Laboratory for Human Performance Research at Perm State University, University Park, PA 16802. Kris-Etherton is with the Dept. of Nutrition at Penn State U. Shiveiy is now with Pepsi-Cola International, Valhalla, NY 10595. Request reprints from Dr. Farrell.