Carb-Protein Drink Builds Muscle After Aerobic Exercise
It is well established that coingestion of carbohydrate and protein after resistance exercise stimulates muscle protein synthesis more effectively than ingestion of protein alone. The reason is that while protein is the primary structural constituent of muscle cells, carbohydrate stimulates the release of insulin, an anabolic hormone that initiates the process of muscle protein synthesis. Researchers from Canada's McMaster University recently investigated whether carbohydrate and protein coingestion would stimulate muscle protein synthesis after aerobic exercise, as well.
Six male subjects completed two-hour stationary bike rides on three separate occasions. After one trial they drank a carbohydrate solution in sufficient quantity to provide 1.2 g of carbohydrate per kg of body weight. After another trial they drank a carbohydrate-protein drink that provided the same amount of carbohydrate plus 0.4 g of protein per kg of body weight. And after the other trial they drank a carbohydrate solution in sufficient quantity to provide as many total calories as the carb-protein drink but without any protein.
The researchers found that the carb-protein trial resulted in a higher rate of protein synthesis than the two carbohydrate trials, and that only in the carb-protein trial was whole-body net protein balance positive. This means that there was a net muscle gain in the post-exercise period when a carb-protein drink was consumed and a net muscle loss when only carbohydrate was consumed. The study was published in the Journal of Applied Physiology. |
