Canarygirl, I do 60-80 mile rides on the weekend, training for the Sam's MS150 charity race. I had to get The Paleo Diet for Athletes by Loren Cordain, which has endurance athletes taking in high-glycemic carbs before and after races. Cavemen did not run for hours on end, so we have to cheat a little.
I eat a Clif's Bar and drink some whey an hour before riding, drink a sport's drink like Gatorade during, and keep eating Clif's Bars every hour or so during the ride. I take in banana and whey after, and stay Primal the rest of the time.
I gotta say that the rides are actually slowing down my weight loss. On weeks when I get rained out, and I just do weight-lifting and sprints, I seem to lose a lot more weight. I'm down 25 pounds so far.