djeclipse said:
So the only thing you changed was more protein? Interesting.
no. I started doing DC training. Actually, the key for me is higher fat (and protein) intake. I made the mistake of letting something a gym buddy of mine said get into my head. He said I looked like I got bigger and I told him I changed my training and diet. Told him about high protein, moderate fat lower carbs and I gained like 10-12 lbs in 12 weeks. Then said that I hadn't gained any more since then (it had only been another 3-4 weeks at that point)...he said I needed more carbs, OMG, my body is just lacking fuel, blah blah...
So, I made the mistake of increasing my carbs, and since I don't eat fats with carbs, I consequently lowered my fat intake. Now, it's been about 4 months since I've gained anything.

I just started going back to what made me gain.
So, no, not just protein, but protein is what you need to build muscle. Like I said, we (PL'ers and BB'ers) have MUCH greater caloric needs than ordinary people. I've never known any of us that can become 250+ lb. monsters on a 2000-2500 calorie normal person's diet. I suppose there are some genetic freaks out there that would grow to 250lbs. drinking water and eating bread though.
Diet is a very individualized thing. There are generalities that everyone can follow, but for dialing it in after you reach a certain level and are trying to push beyond, you gotta tailor it to the individual.