I find that I generally can eat what I want during cycling season, but I have to put in about 8 to 10 hours a week. Also, the part about sports gels and such is also something to consider. If I'm out for less than 90 minutes than water is sufficient. Certain exceptions do apply, like excessively hot weather or race pace. A lot of it is experimental, and you have to do the experiments to see what works for you.