I think one can easily overestimate how many calories are needed and end up gaining, not losing.

I always bring one more bar than I think I need on every ride. The worst thing that can happen is to get caught out without enough fuel to get home. It doesn't mean I have to eat it. I almost always come home with the extra bar, but a few times it has saved my ride, or someone else's ride. I find I need about one 180 calorie bar for every 20 miles plus a light good quality sports drink in my bottle.... one bottle every 20 miles as well.

Within 30 minutes of completing my ride I drink a recovery drink... usually whey protein blended with milk and some frozen fruit and a couple of extra vitamins for good measure. This not only fuels my recovery, but keeps me from eating everything in sight. Cycling stimulates my appetite. Protein satisfies my cravings.

After the recovery drink, I return to normal eating habits. I reward myself in other ways... usually I sit down with a good book and a cup of hot coffee for a half hour.