I eat on the bike, something like 200 cal./hr usually, then have a recovery drink if it's a long ride, just 15g whey powder in water for a short one. Then small frequent meals, like others suggest. For me, the trick is not to get really hungry. I'll usually have that 15g of whey in water about 1/2 hour before every meal, then have a small meal. I'll have a good balanced snack a couple hours before a ride, too. If you're a meat eater and don't like the idea of whey, substitute about 60 cal. of lean chicken or turkey.