A mainstay of effective and convenient nutritional programs for serious athletes, Muscle Milk is an "evolutionary" muscle formula that promotes efficient fat burning, lean muscle growth and fast recovery from exercise. Designed after human mother's milk, Muscle Milk is the perfect and complete protein supplement for your nutritional needs. Lean Lipids promote lean muscle growth and enhance the retention of minerals needed for muscle contraction. The calories are more likely to be burned for muscle energy than stored as fat. There are no empty calories in Muscle Milk. (from Cytosport)