I remember when I first started riding, getting a bit lost & turning a 12 mile planned ride into a nearly 25 mile ride. There was an ice cream stand at about mile 20 & I desperately needed the calories.
As I've put more and more distance riding under my belt, I find that my body has learned to cope with less food on a ride. I often set out on a 60 mile (3.25 hour) ride with just water in my bottles. Most of the time, this is in the morning with only a cup of black coffee since the night before. I've done 80 miles on just water with no serious problems, but was mentally concerned while doing it.
Presumably this is my body using the energy stored in my liver for fuel. I don't know if this is something I've trained my body into doing (I used riding to lose weight, so I was always trying to keep my food intake down unless the distance got over 50 miles or so) or if it's a fairly normal occurance for LD riders.
How far are you comfortable riding with only water & no calorie source? Am I a freak or is this pretty normal?