Carb Loading for Athletes

By Marie Spano, M.S., R.D., Contributing Editor

Many athletes can replace their glycogen stores by consuming an adequate amount of carbohydrate over the 24-hour period after a bout of exercise. However, athletes who train twice a day, have back-to-back training sessions or train hard every day must pay acute attention to their post-exercise carbohydrate intake. Approximately 1.2 grams of carbohydrate should be consumed within 30 to 45 minutes after endurance exercise and every hour thereafter for maximum glycogen resynthesis (Current Sports Medicine Reports, 2008; 7:193-201). During the time period immediately after exercise, muscle tissue is like a sponge, soaking up carbohydrate due to increased muscle insulin sensitivity and rapid glucose uptake (Journal of Sports Medicine and Science, 2004; 3:131-138). Glucose (or dextrose), sucrose, maltose and maltodextrin are rapidly absorbed in the body and quickly replenish muscle glycogen stores that are used to fuel long bouts of exercise, making them preferential sources of carbohydrate (European Journal of Applied Physiology, 2000; 81:346-351; American Journal of Clinical Nutrition, 1993; 58(1):75-79). Fueling with multiple types of carbohydrate is an effective approach during exercise and it may be an effective approach post-exercise, as well. Studies show consuming multiple types of carbohydrate, as opposed to just one type of sugar, during long bouts of endurance exercise increases carbohydrate oxidation. Each type of sugar has a different transporter within the intestines. Once the transporter for a specific sugar becomes saturated, the glucose-only transporter, for instance, the body cannot handle any more glucose at that time (Sports Medicine, 2000; 29(6):407-424; Medicine and  Science in Sports and Exercise, 2004; 36(9):1,551-1,558). By combining multiple sources of carbohydrate, the body can rapidly utilize more carbohydrate.

While carbohydrate is essential for endurance athletes and those engaging in multiple bouts of intense exercise, it also plays an important role in recovery for strength and power athletes. And, though carbohydrate may not further augment muscle protein synthesis if adequate protein is consumed post-exercise, carbohydrate will help replace muscle glycogen used and facilitate greater training adaptations over time (American Journal of Physiology Endocrinology and Metabolism, 2007; 293:E833-E842).

To read more about the nutrients that benefit athletes of all levels, click here to download the December 2012 issue of Food Product Design in the SupplySide Store. 

Marie Spano, M.S., R.D., CSCS, is a nutrition communications expert whose work has appeared in popular press magazines, e-zines and nutrition-industry trade publications. She has been an expert guest on NBC, ABC and CBS affiliates on the East Coast. For more information, visit mariespano.com.