As a performance booster, protein drinks come up short

The one-two punch of carbohydrates and protein aids in muscle recovery during and after workouts -- so combining both in a sports drink was only a matter of time.

But a new study casts some doubt on the effectiveness of this double-barreled approach.

“Certain kinds of protein stimulate insulin release, which is important for muscle glycogen replacement” following exercise, said Martin Gibala, lead author and associate professor of kinesiology at McMaster University in Canada. But ingesting protein during activity doesn’t appear to have the same effect, he said.

The research, published in this month’s issue of Medicine & Science in Sports & Exercise, was funded by sports drink giant Gatorade. A 2004 independent study also published in the journal had found that a protein-laced sports drink did improve performance, and a major competitor has added protein to some of its sports drinks.

The current analysis consisted of a double-blind study of 10 experienced cyclists who rode in three 80-kilometer time trials on stationary bikes. In separate tests, the athletes were given a drink with 6% carbohydrate (as in traditional sports drinks), 6% carbohydrate and 2% protein, and an Aspartame-sweetened placebo drink providing no energy.

The carbohydrate-enhanced drink did improve performance over the placebo, but the addition of protein had no measurable effect. Athletes logged the slowest times when drinking the placebo.

Protein may not as easily absorbed during exercise as carbohydrates, according to Dr. William O. Roberts, associate professor of family medicine at the University of Minnesota, and past president of the American College of Sports Medicine.

“During activity your plan is to fuel the system as sufficiently as possible,” he said, and protein is not as readily available an energy source as carbohydrates.

Even weekend warriors could be affected by the study findings, said Gibala. “The mechanisms of why they get tired are the same as why elite athletes get tired,” he says. “For the average triathlete, sports drinks might be helpful in a race, but there are implications for everyday athletes as well.”

Protein, Gibala added, “is a very hot topic” in the exercise science community. “We’re seeing more and more evidence that protein has a place in recovery,” but more study needs to be done to determine how.