The argument goes something like this: depending on your caloric balance your body is either in a net
state of anabolism (building new tissue) or catabolism (breaking down tissue)
Namely, protein synthesis naturally declines during a hard workout, but if you consume an adequate amount of protein before you begin your session, this can help prevent the exercise - induced
dwindling of anabolism.
This
balance of anabolism (building) and catabolism (destroying) must be tipped toward anabolism if you want to gain muscle mass.
The figure below shows that the whey resulted in a higher
level of anabolism than the soya protein and carbohydrates.
It contributes to muscle wasting because of the breakdown (catabolism) which occurs more rapidly and
lack of anabolism, or increasing muscle tissue repair and rebuilding).
Slow digesting proteins are superior when it comes to maintaining your body in a
state of anabolism.