I eat relatively little on a ride. I don't usually eat before I start if it's in the morning. On a 30-40 mile ride, I will eat one Luna bar after about 12 miles; another after about 15-20. I only drink water. I try to eat about 200 calories an hour, since I've read that 200-300 calories an hour on a ride is about all your system can digest, and I never seem to want more than that. My longest single ride is about 60 miles; longest tandem ride in a day 206 miles. I've never bonked. My doc, a major cyclist and climber, used to date a guy on the Olympic Team nutrition committee, or whatever it's called. He also said that if you eat stuff like PB&J and drink water, you'll be fine electrolyte-wise. I am not a big believer in sports drinks or supplements, although I know many people who are. I've yet to feel the need for them, except for electrolyte capsules on a hot day. I've read articles saying that cyclists often overestimate their calorie needs and eat more than they need.

All that is to say---you'll need to work out what works best for you, since everyone seems to deal with it differently. Listen to your body and it will tell you what you need...