I have not been training long enough to know much about it
but
Based on a doco I watched last night, "I want to look like that guy"
From what I could tell the trainer had him on a clean maintenance diet (based on his starting body fat %) through a short bulking phase of 18 weeks, and then for I think it was 24 weeks his calories gradually lessened until he was at 1900 at comp time. Obviously he was nothing compared to an advanced body builder but he sure did have a developed physique for the time he had been training, I don't see how he could have put all that muscle on during the bulking phase only.
Its only hard if you dont know how.