Most powerlifters I knew would eat whatever they want (lots of meat though), and just by training really hard we would be strong and feel fine. I thought we were all good examples of why nutrition wasn't too important for lifting.
Our only thing would be to quit boozing for 12-15 weeks before comps.
Finally I tried a diet of 5 meals per day, high protein, med carb, low fat. Different protein souces (fish, beef, chicken, egg-whites, and powder), different carbs (bread, pasta, rice, etc etc).
I did it for 15 weeks and my weight stayed the same, I got super lean, and all my training went perfect. The difference was amazing, and I wasn't eating total crap before, just not really paying attention to it.
Everyone I knew tried that diet after that. I wish I tried it earlier.
Of course that has nothing to do with a low-protein "whole food" diet. That can't work!