The bigger the meal, the more calories your body will have to use as energy to regulate body temperature and stay warm. Plan to enjoy heavy meals like biscuits and gravy or beef stew that will leave you feeling satisfied. At night, have snacks handy to combat dropping temperatures.
Don't forget to drink enough fluids. Staying hydrated is essential to keep your core temperature elevated. Warm beverages like coffee, tea and hot chocolate are fine every now and then, just make sure you don't skimp on your water intake. Alcohol will dehydrate you, so just say no to that extra gulp of whiskey, no matter how warm (and fuzzy) it makes you feel.