I was responding specifically to the parent's assertion that "most people are at least somewhat dehydrated a large majority of the time."

I consider that statement equivalent to asserting "widespread dehydration" of the nation's populace. So I stand by the material I quoted.

> People do get dehydrated.

Of course they do, just like they get hungry when they don't eat. But we're discussing drinking water in excess of thirst. I'm not sure I understand what you mean by your last paragraph. The discussion here is about health primarily in the first world, not about the hydration problems in many developing countries.