Personally, I find I don't need to eat anything unless I'm going out for 40+ miles (at at moderate pace). In that case, I will have cereal with milk or buttered toast, a little fruit, and coffee, then eat something starting at 20 miles and every 10-15 miles thereafter. If I know I have a good lunch stop coming up, I might skip one of those feeds, then take a break for lunch.

My wife, on the other hand, needs a substantial breakfast and then some food every 10-12 miles or her blood sugar tanks. We're all different. Keep track of what you eat and when, and how you feel, and adjust accordingly. One of the least pleasant rides I ever had was an 80-miler in the Berkshires where I had a black bean and chicken wrap for lunch (about mile 25). I'm not sure whether it was because the wrap had been prepared badly, or just the ingredients not sitting well in my stomach during all those climbs, but I could barely choke down Gatorade and shot blocks for the rest of the ride--a tragedy, since I passed a great ice cream shop on the way home (mostly downhill). I've decided to avoid so much fiber in the future. A good BLT, on the other hand, is an excellent mid-ride meal, if you pass somewhere that does it right.