I ususally have a 140 calorie South Beach Bar for a 2 - 3 hour ride. I usually go have Subway or some other lunch after the ride.
For a 100 mile ride...I would have a few south beach bars...or maybe a couple of fig newton at each rest stop or more...
I am tyring to lose wieht - so I don't want to consume too many calories as I ride, but I wanted to be able to ride well - and last the whole ride. I use part G2 (low cal Gatprade) and water in my water bottles.