So I've done some research into gaining muscle without adding extra fat and I've been told the best way to do it is by eating 500 calories more than my maintenance calories a day on training days, and 100 calories more than maintenance calories on rest days. The article author also said that naturally you can only gain 1-2 pounds of muscle a month? This may be common knowledge but is very new and suprising to me. The article is http://www.fitmole.org/the-lost-art-of-lean-bulking-how-to-gain-muscle-without-fat/