I read about that yesterday and thought this was interesting on smh:
Eight glasses of water advice 'nonsense':
"Not only is there no scientific evidence that we need to drink that much, the recommendation could be harmful, both in precipitating potentially dangerous hyponatremia and exposure to pollutants."
So he claims that too much water can even be harmful. I used to try to force down water, but now I just drink when I'm thirsty. But even so, I usually drink 2-3L a day.
However, that study aside, is the advice of just listen to your body always best? What about for people who have no desire to drink any water during the day at all? For many fat people, who are always hungry, listening to their body telling them to eat all the time, is not the best idea for example...