Muscle is built outside of the gym and ample recovery is critical. What you do in the gym is destroying muscle and with proper nutrition and rest you'll be able you to complete your gains. After a workout session you have approximately 30 minutes to help replenish lost glycogen stores, replace energy nutrients and preserve lean muscle tissue. Most brands of chocolate milk supply around 20 to 25 grams of carbohydrates and between 8 and 11 grams of protein (per 8 oz.), which makes for an optimal post-workout replenishment choice. Another key selling point to chocolate milk is that it comes from cow’s milk, which contains about 80% casein protein and 20% whey protein. Whey protein amino acids are immediately shoveled right into the muscles and casein protein amino acids are digested slowly over time.