In retrospect, my diet was the one thing I never truly attempted to improve while I was running competitively. I lived off of hamburgers, pizza, and way too much soda. About the closest I ever came to modifying my diet for my training was eating pasta dinners before meets.
I never experienced any major setbacks as a result of my diet, but I have no way of knowing how many minor hurdles I was putting in my way by eating the way I did. I think I was probably just lucky. I certainly never had an experience like Anthony Famiglietti, who talked about the diet-induced problems he experienced in this must-read article with Joe Battaglia at Universal Sports.
I wouldn't wish his experiences on any runner, even if he wouldn't trade them now. I'd much prefer young athletes learn from his experiences to realize that certain behaviors, if practiced with consistent quality, will ensure optimal training. And yes, maintaining a healthy, balanced diet is indeed one of the behaviors that requires consistent quality!