Karfonta, K., Lunn, W., Colletto, M., Anderson, J., & Rodriguez, N. (2010). Chocolate milk and glycogen replenishment after endurance exercise in moderately trained males. Presentation 862 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.

The purpose of this study was to compare muscle glycogen content after consumption of either fat-free chocolate milk or an isocaloric non-protein drink after an endurance exercise bout. Moderately trained male runners (N=8) consumed a eucaloric diet providing 1.5 g of protein per kilogram and approximately 6 g of carbohydrate per kilogram for two weeks. At the end of each week, Ss performed a 45-minute run at 65% of VO2peak after which 16 ounces of either fat-free chocolate milk or a non-nitrogenous, isocaloric carbohydrate-only control beverage was consumed.

Immediate post-exercise muscle glycogen concentrations before beverage consumption were not different between treatments. Glycogen concentrations were greater for the milk condition at 30 and 60 minutes post-exercise than for the control condition. Although blood glucose concentrations before beverage consumption were not different, glucose concentrations were lower for the milk condition at 30 and 60 minutes post-exercise when compared to the control.

Implication. The ingestion of fat-free chocolate milk following an endurance exercise bout supports glycogen replenishment to a greater extent than a non-nitrogenous, isocaloric beverage. While the benefit of carbohydrate supplementation on glycogen replenishment following endurance exercise is well-established, a mixed carbohydrate-protein beverage may provide additional advantages to muscle recovery.

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