Augment a strength-training program with supplemental protein and you just might increase the rate at which your body builds lean mass. The International Society of Sports Nutrition recommends whole foods as your primary source of protein, but it also declares that if you use supplements, whey and casein are best. These two proteins, derived from cow's milk, digest at different rates and complement any muscle-building program with their positive effects on muscle growth and recovery.
Protein is made up of amino acids. Certain amino acids, particularly branched-chain amino acids, are particularly important in your body's ability to maintain muscle tissue. Whey protein contains a high proportion of these amino acids. Whey is also fast-digesting, meaning it processes through your body quickly and gets to worked muscles expediently if you consume it right after a workout. Your muscles use these amino acids to begin the repair and building process as soon as you put down the weights.
Casein also contains all the essential amino acids that your body cannot produce on its own. It doesn't digest as quickly and readily as whey protein, however. When you're trying to build muscle, this slow digestion rate can be an asset. Whey protein provides your muscles with an immediate supply of amino acids when consumed after a workout, but casein releases more slowly so your muscles continue to receive a steady supply of amino acids for as long as seven hours after your workout. This slow release may help reduce muscle damage and soreness, so you recover faster and tolerate a greater workout volume and frequency -- contributing to growth. Consuming casein just before bed can also prevent the muscle breakdown that may occur while you sleep.
Both whey and casein prove their muscle-building abilities in research. A review published in the "Journal of the American College of Nutrition" in 2009 noted that milk proteins are superior to soy protein when it comes to achieving greater muscle mass gains with resistance training. A 2004 issue of "Medicine and Science in Sports and Exercise" published a study showing that, despite their differing effects on amino acid balance in the body, both casein and whey consumed an hour after a workout resulted in similar increases in net muscle protein synthesis. Protein synthesis is necessary for the muscle-building process. A later study from 2006, also published in "Medicine and Science in Sports and Exercise," determined that drinking milk one hour after a leg strength-training routine enhanced muscles' ability to go into protein synthesis and build muscle. This suggests that a combination of the two proteins in milk, whey and casein, are effective for muscle building.
Time It Right
Drinking milk or its isolated proteins alone won't result in big muscles. You need to strength train diligently to build lean muscle mass. The International Society of Sports Nutrition recommends that you follow a strength-training program for at least 10 to 12 weeks that consists of three to five days per week of lifting. Use compound exercises for both the upper and lower body during this exercise protocol. Compound exercises are those that activate multiple joints at one time, such as squats and presses. Consume the whey or casein and whey protein powder within 45 to 90 minutes of finishing each session for optimal uptake and use of the amino acids.