Hey guys. I'm a skinny dude that's been training for about 5 months. In that time I've gained about 10-12 lbs. or so. I attribute these gains to hard work in the gym (3-4 days a week) and an increased diet (primarily due to supplements like weight gainer shakes). I recently ran into a friend who critisized me and called me naive for drinking protein/weight gainer shakes.
He said "they don't work" and just "pass through your system". He basically told me I was just wasting my money. I personally think they've been the main reason that I've gained weight, but since I don't properly understand the science behind the nutrition, I couldn't defend myself.
Can someone explain to me the science behind whey protein shakes, and if they have an advantage over eating a regular meal after a workout?