64 ounces of water a day?
Does anyone know of any research that demonstrates a need for everyone to drink 8, 8-ounce glasses of water a day? I've got serious doubts and suspect it may be more harmful than beneficial. Perhaps I have missed something. But using a paleolithic model, it seems unlikely that our Stone Age ancestors would have had access to that much water daily given that watering holes are where predators hang out. I would suspect they got little more than a few ounces daily and that was a challenge. Most of their water would have come from their food and small sources such as the dew on leaves, I believe. If this assumption is incorrect, then how is it they thrived for 2 million years eventually populating the planet, but we now have to have 64 ounces a day to be healthy?
How about the oft-repeated stipulation that none of this water can come from caffeinated beverages as they cause a net loss of body fluid? Again, I have never seen any research that supports this notion. Has anyone? In fact, I have found one study that contradicts this belief during exercise (Falk et al, 1990, Effects of caffeine ingestion on body fluid balance and thermoregulation during exercise, Can J Physiol Pharmacol 68(7):889-892).
There are lots of other things that we have been told repeatedly for so many years that everyone now assumes them to be well-supported "facts." I'll get around to them at another time. But for now I'm wondering about all of these people I run into carrying half gallon jugs of water which they sip on all day long until empty and finally go to bed with a mission accomplished.
Can anyone set me straight by pointing out research that supports this notion?