Actually water and the whole “if you’re thirsty you’re already dehydrated “ thing IS controversial (or should be.)
So many humans force fluids and just as people above have said about plants and how their needs are affected by their specific environment, our need for fluid is very variable. We get thirsty when we need to drink. There’s no right amount of water, and no two people are the same.
If we do not get thirsty, or are frequently thirsty, those are signs of imbalance. But how can we possibly know if we are thirsty if we are constantly forcing fluids? (As most people are.)
This is something I run into all the time in my practice as an acupuncturist and herbalist. I’m not going to weigh in about food (even though in my training food is seen as medicine) because again, no one size fits all. The zillion food fads out there can be a real hazard!