Drinking recovery drinks, and eating carbs to recover after a 25-35 mile ride is a significant reason that a lot of cyclists are fat.

Go out and do a hard 100 miles, and if you're going to do it again tomorrow, you need a recovery drink or some carbs to take advantage of replinishing glycogen stores.

1-2 hour ride, particularly if you don't have a big ride the next day, just eat a normal helathy diet.