didn't actually eat any more than I would have done when at home, but I felt the need to eat earlier, and not get hungry. Getting hungry means getting cold and weak, weak means having trouble generating heat, which means even colder. I enjoy both biking and skiing when it's cold, but I find I have to be more careful about eating protein and fat-rich food in advance, I have to stay "stoked up" on food, and I have to avoid sweating a lot, either by moving a bit slower or by removing excess clothing early enough. None of these things matter much when it's above freezing.