T-nation had a good article on this a while back.
The basic idea is that, as a natural, your body is only capable of building so much muscle so fast no matter how much you train and/or eat.
Hence, eating more – even good foods – will help only to a point.
Beyond that is pointless.
So while it's true that you DO have to eat sufficient amounts to grow, don’t make the mistake of thinking that you can train more frequently and build more muscle faster by eating more.
Without the drugs, you won’t get the same benefits.