I would recommend not skipping meals, but not eating heavily at them. Snack frequently, if possible, on some good carbs (fruit would be included, as well as whole grain products if possible; brown or basmati rice, small servings of pasta). For all the exertion, definitely the majority of your diet should be complex carbs, but with a little easy-to-digest type of protein, which will serve as a longer-lasting form of energy that releases over more time than the shorter-lived carbs. Perhaps the bulk of the protein at night or after the day's activity is done (think lean meats, eggs), then lean on the carbs for the pre-activity meals. Some 'good' fats won't hurt you at all, either - this is where you can feel free to eat granola, nuts, peanut butter, etc., since your body (and brain) will be using it all!