I’ve read some recent articles saying that the 8 glasses of water/day thing is a myth. The closest source that I could find for the recommendation came for WW2 soldiers carrying their packs…the army decided it took 8 glasses of water per day to keep them hydrated. I could not find any clinical study stating how much water a person should consume each day. Yeah, you can find several nutrionists and MDs who say to drink 8 glasses per day but they themselves can’t find any credible source for this recommendation. Anyone know the legit source for the 8 glasses of water/day recommendations?
The RDA originally (I say originally because I’m not 100% up to date, but to my knowledge there has been no changes.)determined that the body needs one mL of water for every kilocalorie burned in metabolism.
Some journalist did some research on this “8 glasses of water a day” recommendation about a year ago wondering where in the hell it came from since nobody who made the recommendation could tell from where it originally came. This RDA research was the only thing he could find.
8c of water = 64 oz
64oz x 30(mL per oz) = 1920 mL
So the recommendation provides enough water for a person who burns 1920 kcal a day(pretty low really, unless you’re a geriatric)
But…
A phrase following the 1 mL water per kcal recommedation stated that most of this water can come from food sources. This makes it just about impossible to calculate how much free water someone needs to intake since most foods are mostly water.
So who knows?
Sorry I don’t have any cites for this. This is strictly what I remember from an interview I heard on NPR and a magazine blurb probably in TIME?(and my backgroud in dietetics).
I can’t remember the journalist’s name, but he made the interview rounds about a year ago…I heard him on NPR(KERA Dallas). I’m not even really sure if it was a magazine article or part of a book?
So take all that for what you will. I doubt the original RDA research is on the web, but you might try searching the NPR or KERA dallas websites for more info.
This has been discussed before:
http://boards.straightdope.com/sdmb/showthread.php?threadid=118397
http://boards.straightdope.com/sdmb/showthread.php?threadid=130164
http://boards.straightdope.com/sdmb/showthread.php?threadid=2525
I thought Cecil did a column on this but I can’t find it right now.
Here in Southern Arizona, a person who is active physically outdoor will need a lot more than 8 glasses. On a hot day, even though I drink water pretty steadily, I find myself drinking 4 to 5 16 oz glasses just to catch up. On those hot days, I try to drink as much fluid in the morning before going outside.
When I lived on the Redwood Coast of Northern California, drinking water was a thing that I paid no attention to…of course it was very often foggy/misty/raining.
So…ya gotta adjust to what the climate and your activity dictates. 8 glasses a day is not cast in stone.
Here in Southern Arizona, a person who is active physically outdoor will need a lot more than 8 glasses. On a hot day, even though I drink water pretty steadily, I find myself drinking 4 to 5 16 oz glasses after dinner at night just to catch up. On those hot days, I try to drink as much fluid in the morning before going outside.
When I lived on the Redwood Coast of Northern California, drinking water was a thing that I paid no attention to…of course it was very often foggy/misty/raining.
So…ya gotta adjust to what the climate and your activity dictates. 8 glasses a day is not cast in stone.