by Edmund R. Burke, Ph.D.
Drinking a carbohydrate sports drink right after a tough workout in the gym is a great way to replenish fluids, but it may not be the best way to replenish the fuel in your muscles. That is, unless you consume some protein along with the drink.
In a study done by exercise physiologists Donovan Fogt from the University of Texas, endurance cyclists rode a grueling 2 hours on stationary bikes, depleting their muscle-glycogen stores. Immediately following exercise and again 2 hours later, the riders drank 12 ounces of a carbohydrate-protein beverage (53 grams of carbohydrate and 14 grams of protein) or a carbohydrate sports drink (20 grams of carbohydrate, no protein).
When the researchers extracted muscle samples from the cyclists 2 hours after the exercise session, they found that the carbohydrate-protein beverage resulted in a 128 percent greater restocking of glycogen compared with the carbohydrate only sports drink. The combined dose of carbohydrate and protein helps boost insulin levels, which in turn acts indirectly to stimulate glycogen rebuilding. Also, insulin aids the recovery and repair of proteins that may have been damaged during exercise.