if you don't really feel like you need it, then no. Personally, after about 40 miles, I'm gonna bonk if I don't eat a cliff bar or something. I like to stop and eat at around 30 miles if I can so I know I won't bonk suddenly. I've done it before and I'm lucky I didn't pass out right on the bike and have a nasty crash.
You generally don't use as much water in the cold, but you still burn as many if not more calories, so the need for extra food is there on longer rides, even if you don't go through as much water.