Although you may be asleep, your body continues to digest and absorb protein. However, this is only if you consumed protein before bedtime. The ideal type of protein for nighttime use is a slow-absorbing protein, such as casein, because it provides a constant flow of amino acids -- the body's usable form of protein -- to your muscles during the eight or more hours you sleep.
Absorption
Your digestive system continues to process protein as you sleep. How long this process occurs depends upon the type of protein you consumed before going to bed. A fast-absorbing protein, such as whey, is fully digested and absorbed within about 1.5 hours of being ingested, according to muscle development expert Helen Kollias, Ph.D. A slower-absorbing protein, such as casein, takes much longer to absorb, which is why it is commonly used by bodybuilders as a nighttime protein supplement. According to Jeff S. Volek, Ph.D., R.D., casein continues to supply amino acids -- the building blocks of protein -- to your muscles for 7 hours or longer as you sleep.
Growth Hormone
Growth hormone, or GH, is the primary hormone associated with growth and development in your body. It is particularly important when it comes to muscle growth. According to Colorado State University, the release of GH by your body is most intense during a deep sleep. To support muscle growth, you must also have an adequate amount of amino acids flowing to your muscles while you sleep. Knowing these facts, you can maximize your muscle gains overnight by ingesting a slow-absorbing protein before you go to sleep.
Rate
Different types of protein absorb at varying rates. Whey protein, for instance, absorbs at a rate of up to 10 g per hour, according to Dr. Kollias. Casein absorbs at a much slower rate, states Dr. Volek, because of its gelatinous composition that tends to bind to the walls of the stomach and intestines. Other slow-absorbing sources of protein that may be ideal for a pre-bedtime snack include milk, chicken, turkey or lean beef.
Considerations
Not all protein you consume will get absorbed whether you're asleep or not. If you consume more protein than your body can process, the excess protein is wasted. It can get stored as body fat or excreted from the body. According to the University of California Los Angeles, your body can absorb up to 0.91 g of protein per pound of body weight per day. For example, a 190-lb. person can consume up to 172 g of protein per day. To maximize absorption, always divide your protein intake equally among each of your daily meals.
