About Whey Protein
Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production.
Whey protein typically comes in three major forms: concentrate, isolate, and hydrolysate.
- Concentrates contain a low level of fat and cholesterol but, in general, have higher levels of bioactive compounds, and carbohydrates in the form of lactose — they are 29%–89% protein by weight.
- Isolates are processed to remove the fat, and lactose, but are usually lower in bioactivated compounds as well — they are 90%+ protein by weight. Both of these types are mild to slightly milky in taste.
- Hydrolysates are predigested, partially hydrolyzed whey proteins that, as a consequence, are more easily absorbed, but their cost is generally higher.  Highly-hydrolysed whey may be less allergenic than other forms of whey. They are very bitter in taste.
Whey Protein Muscle Building Study
Whey is essential in the bodybuilding world today because of its ability to be digested very rapidly. This allows the protein to become available for muscle building very quickly. Most commonly it is used after workouts to help increase levels of amino acids in the blood, which are taken up by the muscles to ultimately increase mass. In addition, during exercise, whey helps open up blood flow by inhibiting an angiotensin-converting enzyme which originally constricts blood vessels; this allows better flow of nutrients to necessary areas to help repair and rebuild muscle tissues.
This new study challenges the previous research suggesting that eating whey only has muscle building benefits within a couple hours of eating it.
Researchers at McMaster University in Canada and the University of Nottingham in England recruited 15 young men, all experienced in performing resistance exercise.
The participants underwent testing to measure the rate of muscle building under two conditions: after eating 15 grams of whey protein at rest and 24 hours after a round of resistance exercise.
During the exercise portion of the study, each participant performed these activities: lifted a heavy load on a leg extension machine until fatigue; a light load until fatigue; or a light load in which the workout session was stopped before fatigue set in.
Whey Protein after Workout
Each man returned to the laboratory 24 hours later and ate 15 grams of whey protein, a common dairy constituent.
Results indicate that regardless of the type of exercise load, muscle building increased after eating whey protein.
The findings suggest that muscles may make better use of dietary amino acids eaten 24 hours after exercise, regardless of exercise load as long as the exercise is being performed until fatigue.
The researchers say their findings suggest insights about how exercise can provide benefits to lean muscle mass growth and muscle maintenance.
SOURCES: News release, McMaster University. Burd, N. The Journal of Nutrition, April 2011.