I was doing a 6 day on 1 day off schedule during the last 6 months training each body part twice a week:
chest/back
biceps/triceps
legs/abs
chest/back
biceps/triceps
legs/abs
OFF
My diet was what I like to call a modified version of Atkins. I was eating all the eggs, chicken, fish, and beef I could get down. But I tried eliminating carbs altogether (e.g. potatoes, rice, pasta, sugar, fruits, grains, etc).
I think what gave me the best gains was only using basic compound exercises with the heaviest weights I could lift with reasonably good form vs. isolation techniques. So for chest I wasn't doing anything but wide and close grip flat bench sets, for back I was only doing wide and close grip pull ups, etc...