Restocking spent glycogen stores is a major part of exercise recovery for endurance athletes. Glycogen is a vital source of energy for working muscles, especially at higher intensities. Evidence suggests that co-ingesting carbohydrate and protein after exercise may stimulate greater glycogen synthesis during recovery than carbohydrate alone.

How? The amino acids that make up dietary protein can encourage the pancreas to release more insulin, thereby increasing muscle glucose uptake and, in turn, glycogen production within muscle cells. But there’s a catch: As reported in Medicine & Science in Sports & Exercise, this recovery tag team only works to its full potential if protein does not replace any of the energy coming from carbohydrates.

This means 100 grams of carbohydrate and 30 g of protein could stimulate more glycogen synthesis than 70 g of carbs and 30 g of protein. So prudent sports nutrition advice for athletes is simply to add protein to their lofty post-workout carbohydrate intake instead of removing some carbs to make room for protein calories.