My son is fairly skinny (125 lbs, 4 feet 9 inches), and he has been working out. He has seen some results, but he is not gaining much weight nor is he getting "big" (a little cut but not really bigger and stronger and more muscular).
A trainer suggested that he buy whey protein powder and have a shake an hour? before and right after he works out?
First, is this healthy? Is this a good way to get the most out of workouts, and to gain some weight without getting fat. If so, when should he have the shakes? Also, how long should he have them for? Should he take them every time he works out? After a few months, if he stops having the shakes, will the results last without continuing to have them? Separately, will his body rely on them in the future to build muscles?
Lastly, is one powder better than another? Where can I get good whey protein?