Here's what works for me, YMMV.
I carry 2, 1 qt canteens with me, both of which start out half water and half ice, and I keep a 5 gallon cooler in the car that is half ice half water, when both canteens are empty, or close to it, I refill next time I'm at the respawn, every 3rd canteen I throw in a small fast food joint pack of salt and use that for electrolyte restoration (in a 12 hour day I'll go through 6-7 quarts of water). I carry several carb gels, or energy beans with me and use one every 2nd canteen, and I carry some jerky, and Clif bars with me to snack on, and I will break after around 5-6 hours and get a good full meal into me (a mix of protein and carbs, as well as some sugar). I always keep a pack of wine gums with me as a treat for the end of the day on the ride home, just to restore some sugars, and I keep several NuuN tablets with me for emergency use if needed.
It's worked for me for years, but every person is different, and will need to find their own balance.
When a show of teeth is not enough, be prepared to bite.