Protein

Let's look at the science behind protein powders. It was thought that eggs had the highest biologic value for protein. It was assigned a value of 100 and all other proteins were compared against it. It was then determined that whey protein had a higher biological value and whey isolate was assigned a value of 159. Soy protein has a BV of 74. Therefore, the most effective protein for immediate protein replacement is whey isolate.Sustained protein absorption is another matter. Egg protein and casein have a slower absorption in the digestive tract.Protein isolates are more quickly absorbed that whole proteins. The limit of 30 grams of protein per feeding was determined by how much protein could be absorbed from whole food sources during the usual gastro-intestinal transit time. With more easily absorbed isolates, this value increases significantly.Soy protein does not have a full complement of essential amino acids and must be combined with other sources like rice milk to round out the profile.

Therefore

1-Chose a protein powder whose taste you like the best
2-Use whey protein before, during or immediately after your workouts.
3-Use slower absorbing proteins before bed-time.
4-Only vegans should use soy protein. Soy also contains phyto-estrogens (say gynecomastia)

Bruce J. Nadler M.D.Los Angeles, CA