Hydration, which requires more than mere water. You need electrolytes and other things to stay properly hydrated. That piece shouldn't be "news" to anyone. We have an entire industry built on producing sports drinks which contain sugars and electrolytes.
I find sea salt is better than table salt. Certain carbs, like aloe drinks, better than sugar per se. And I find that I stay better hydrated when I get enough of the right oils and avoid oils that I personally have issues with. I find butter and palm oils helpful, but I would suggest you try an elimination diet and figure out for yourself which oils are helpful for you as an individual and which are a problem.