Over the course of the past few years, I've learned that if the only thing I ever drink is water, I don't get headaches. If I drink things with caffeine in them, then I get withdrawal headaches when I stop drinking things with caffeine in them, and if I never stop then I just go ahead and get headaches anyway after a few weeks. If I drink things with sugar in them, then I get headaches. If I drunk things with artificial sweetener in them, then sooner or later things with sugar in them seem like a good idea.
I had managed to get down to drinking nothing but one or two cans of diet soda a day (plus as much water as I want). And just as I managed to kick the diet soda habit, I realized that my three favorite beverages: honeycrisp apple juice, tangerine juice, and egg nog - are all in season. So it looks like I'm just going to be living with headaches for the rest of the year.