I'm the same way. It takes me a long time to ramp up for the season and I do fairly strenuous stuff in the winter. I always drink tons more and need to eat more than most people. I am good with just water for 15-20 miles, but only if I am well fed and hydrated before. Over 20 miles, I need energy in my drink, as well as solid food, in little bits as I go. Heat affects me greatly.