Casein Protein

Casein makes up about 80% of the protein in milk (whey makes up the remaining 20%) and is the slowest-digesting protein that you can consume. The reason why casein digests so slowly is that it is in the form of globules that form a clot in the stomach. The clot provides less surface area to the digestive enzymes that break down the protein and so they must chip away at the clot one layer at a time in a similar manner to peeling an onion. The main benefit of this slow digestion rate is that it provides a long, steady supply of amino acids to your muscles, which inhibits muscle breakdown. This is why Muscle & Fitness recommends consuming a casein protein shake before bed. Since you are essentially fasting while you sleep, casein will provide your muscles a steady source of aminos throughout the night, helping to stop the muscle breakdown that normally occurs when you sleep. More recent research has shown that adding casein to a postworkout whey protein shake can further enhance muscle growth. While it’s true that you need a fast-digesting protein like whey after workouts, the slow-digesting protein extends whey’s muscle building properties. Another benefit of casein is its high glutamine content. This amino acid can increase growth hormone production and further promote muscle hypertophy.