In the study, 10 male endurance runners between 24 and 40 years old ran a 20K, 5K, 10K, and 20K over four consecutive days. One group of men ate a diet low in protein—0.94 grams (g) per kilogram (kg) of bodyweight, or about .42g per pound of bodyweight—one group ate a diet moderate in protein (1.2g per kg, or .54g per pound), and one group ate a diet high in protein (1.83g per kg, or .82 grams per pound).
After that, the researchers tested the men’s performance in the 5K distance as a measure of their performance capacity. They discovered that the runners who consumed a high amount of protein ran a a 5K that was about 1.5 percent faster—or about 16 seconds—than those who ate lower amounts.
One possible reason? Those in the moderate and high protein groups “maintained whole-body protein balance,” study author Dr. Daniel Moore, assistant professor of kinesiology and physical education at the University of Toronto, told Runner’s World in an email. This higher protein balance may have been helpful in maintaining muscle strength, in particular, the max contraction of your quads—the muscle group that extends your knees—which can help improve short-distance running performance.
The group who consumed a low amount of protein actually saw decreases in markers of exercise performance after only four days, like muscle contraction, force, and speed, says Moore. Eating too-little protein can throw off your whole-body protein balance. If that lack is sustained over a prolonged period, it could ultimately translate into a loss of lean body and muscle mass.
And while the study only observed men, Moore believes women would see benefits from upping their protein intake, too—though it’s possible it may not be to the same extent as in men.
“We believe that any endurance athlete who trains regularly—most days of the week—and who is interested in maximising their recovery from and adaptation to their training would be wise to ensure they are consuming not only adequate energy and carbohydrates, but also protein,” he said.
Keeping with the results of the study, getting a high amount of protein (1.8 grams per kilogram of body weight) means that if you weigh 130 pounds, you should eat around 106 grams of protein per day. Foods such as chicken, turkey, fish, tofu, tempeh, and beans are all good sources to add to your regular diet to help boost your overall performance, whether you’re training or racing.
This article originally appeared on Runner's World