"Sports drinks improve performance during prolonged exercise because of two key ingredients: carbohydrate, which provides fuel for working muscles, and sodium, which helps to maintain fluid balance," says Martin Gibala, an associate professor of kinesiology at McMaster. "Research also supports the practice of consuming protein after exercise to promote muscle recovery. However, the alleged benefit of consuming protein during exercise is controversial."
The study, which is published in the August edition of Medicine & Science in Sports & Exercise, found that adding protein to a carbohydrate-electrolyte sports drink did not improve cycling time trial performance compared to the sports drink alone.
The research was conducted on 10 trained cyclists who performed a simulated 80 km bicycle race on three occasions. During exercise, the subjects were given a sports drink, a sports drink supplemented with protein, or a placebo drink that provided no energy. The drinks were similarly flavored and neither the subjects nor the researchers knew what drink was consumed during a given test. The study found that the sports drink improved performance compared to the placebo drink -- confirming prior research -- but there was no additional benefit of protein supplementation.
"Previous studies that suggested protein was beneficial used 'ride to exhaustion' tests that do not resemble normal athletic competition. In addition, the subjects in those studies received less than the optimal recommended amount of carbohydrate," says Gibala. "Our study shows that protein confers no performance benefit during 'real life' exercise when athletes consume sufficient amounts of a sports drink."
The study, which was funded by Gatorade, comes at a time when the sports drink industry is under pressure to create new products by adding ingredients that might further enhance performance. Some companies have heavily marketed protein-laced sports drinks as the next magic bullet, but Gibala's research disputes such claims.
"Eating a little protein after exercise is important to help repair damaged muscles and promote training adaptations," says Gibala, "but no compelling evidence suggests that endurance athletes need protein during exercise."
Contact: Jane Christmas firstname.lastname@example.org McMaster University