Absolutely. In fact, milk is one of the best muscle foods on the planet. You see, the protein in milk is about 20 percent whey and 80 percent casein. Both are high-quality proteins, but whey is known as a "fast protein" because it's quickly broken down into amino acids and absorbed into the bloodstream. That makes it a very good protein to consume after your workout.
Casein, on the other hand, is digested more slowly. So it's ideal for providing your body with a steady supply of smaller amounts of protein for a longer period of time—like between meals or while you sleep. Since milk provides both, one big glass gives your body an ideal combination of muscle-building proteins