Whey protein and casein protein are the two driving forces in protein powders on the market today. These protein-packed powders are used for multiple purposes, from supplementing a low-protein diet to assisting in maximum muscle growth through intense resistance training. Whey and casein are two similar, but different, proteins that can work together if used properly.
Whey and casein are proteins that derive from milk. Whey makes up approximately 80 percent of the protein found in milk, while casein makes up the remaining 20 percent. Each form of protein is extracted through a variety of food-making processes. Each form of protein has been extracted commercially for the majority of the 20th century.
Whey protein and casein protein cannot "contain" one or the other, as they are two differing forms of protein. This can be confusing when shopping for protein powders on the market, however. With many protein powders, and especially those with a high concentration of whey, a small amount of casein may be included in the ingredients list. This is not to imply that whey contains casein in any manner; it is only stating that casein proteins are included in the mix alongside of whey.
Whey and casein are both excellent sources of direct protein, but their modes of digestion and body usage differ slightly. Whey is a fast-digesting protein that can take as little as one hour to be absorbed into the body. Casein is a slow-digesting protein that can take as long as seven full hours to be absorbed. Whey is a perfect protein supplement for daytime and after-exercise eating, when your muscles are in their most anabolic state. Casein is a perfect protein supplement to eat just before going to sleep, when your body goes into rebuild mode and you know for sure that you won't be eating anything for several hours.
A study done in 2000 at the University of Western Ontario found that active people who wish to put on as much muscle mass as possible may need as much as 1.6 to 1.8 grams of protein per every kilogram of body weight daily. That means that a 175-pound individual may need a minimum of 127 grams of protein every day. Even multiple hearty meals throughout the day can leave you well short of this amount, making whey and casein powders a powerful ally in building maximum muscle mass.
These protein powders can do a great deal in working toward gaining muscle mass, but they will only help in achieving your desired results if you are putting in the necessary time at the gym. Although whey protein powders are usually low in calories, casein protein powders can be quite high in calories--some pack twice as much per serving. If casein shakes are eaten daily without the regular calorie burn and intense muscle contractions to go along with it, you will find yourself adding on several inches of flab instead of muscle.