New research at the Loughborough University’s School of Sport and Exercise Studies in Leicestershire, Englandshows that skim milk — not water or a sports drink — is the best way to rehydrate after exercise.

Researchers compared skim milk with water and a commercial sports drink. They found that people who drank the skim milk reyhdrated four times faster than with water or the sports drink. That is, people who exercised, then drank milk were fully hydrated in an hour, while those who drank water or the sports drink took four hours or more to rehydrate.

The scientists believe milk’s electrolytes make it so effective.