What is the minimum amount of water needed for a human to survive?

[Khadaji]

I know, I know, we have all heard that we need to drink 8 full glasses of water a day. But what does the average human need to survive daily?

[Ponster]

From Snopes of course !

The origins of the 8-10 glasses per day figure remain elusive. As a recent Los Angeles Times article on the subject reported:

Consider that first commandment of good health: Drink at least eight 8-ounce glasses of water a day. This unquestioned rule is itself a question mark. Most nutritionists have no idea where it comes from. "I can't even tell you that," says Barbara Rolls, a nutrition researcher at Pennsylvania State University, "and I've written a book on water."

Kidney specialists do agree on one thing, however: that the 8-by-8 rule is a gross overestimate of any required minimum. To replace daily losses of water, an average-sized adult with healthy kidneys sitting in a temperate climate needs no more than one liter of fluid, according to Jurgen Schnermann, a kidney physiologist at the National Institutes of Health.

One liter is the equivalent of about four 8-ounce glasses. According to most estimates, that's roughly the amount of water most Americans get in solid food. In short, though doctors don't recommend it, many of us could cover our bare-minimum daily water needs without drinking anything during the day.

[guinnog]

I am glad someone has at last debunked the irrational and nonsensical belief that drinking loads more water than you need will somehow 'purify' or 'detoxify' your body. It is on a par scientifically with crystal therapy.

John

[Stan Doubt]

One liter is the equivalent of about four 8-ounce glasses. According to most estimates, that's roughly the amount of water most Americans get in solid food. In short, though doctors don't recommend it, many of us could cover our bare-minimum daily water needs without drinking anything during the day.

I'll just jump in to say that there is quite a bit of variation in "solid food" intake, particularly with so many people on low carb diets. While it's true that digestion of carbohydrates yields "metabolic water", digestion of proteins actually consumes water, so hydration requirements could vary widely from person to person, depending on activity & diet.

Generally speaking, given the other popular beverage choices in America, a glass of water may not help, but it probably won't hurt quite as much as the sugar-laden alternatives.

[Rucksinator]

Originally Posted by guinnog

I am glad someone has at last debunked the irrational and nonsensical belief that drinking loads more water than you need will somehow 'purify' or 'detoxify' your body. It is on a par scientifically with crystal therapy.

John

Hold on, that’s not what’s been debunked (at least not here). What’s been debunked is the idea that not drinking lots of water will KILL you. I think that most people agree that drinking lots of water is good for you. When the law of diminishing returns kicks in is a matter of (another) debate.

[guinnog]

Originally Posted by Rucksinator

Hold on, that’s not what’s been debunked (at least not here). What’s been debunked is the idea that not drinking lots of water will KILL you. I think that most people agree that drinking lots of water is good for you.

Cite?

John

[Triskadecamus]

Originally Posted by Rucksinator

Hold on, that’s not what’s been debunked (at least not here). What’s been debunked is the idea that not drinking lots of water will KILL you. I think that most people agree that drinking lots of water is good for you. When the law of diminishing returns kicks in is a matter of (another) debate.

Yeah, and most people agree the earth is closer to the sun in the summer. But Argumentum ad Populum doesn't make it so, except in politics. No one has documentation on experimental evidence that extra water is better for you than enough water. There is no experimental evidence of how much is "enough" other than the minimum quoted above.

Water junkies love to proselytize, but they lack facts to back up their claims. Two glasses of water a day is far better for you than six. Why? Because I said so. Do you believe that? Well, my evidence is exactly as rigorous as the evidence for eight glasses.

I met a guy once who would not drink water. Never. He believed that the stuff was bad for you, diluted you blood. He preferred beer. He was eighty years old, and working his third career. Obvious proof that water is bad for you. What "evidence" do you have to offer?

Tris
-------------------------------------
"To teach superstitions as truth is a most terrible thing." ~ Hypatia of Alexandria ~

[Bag of Mostly Water]

In my experience the amount of water you need greatly depends on the amount of salt (sodium) in your diet. If you consume several grams of sodium a day, you could need 3 l of water each day. If your diet is very low in sodium, hardly any water besides what is in typical food is sufficient. However, I can't provide a cite.

[barbitu8]

Originally Posted by Ex_Chemist

In my experience the amount of water you need greatly depends on the amount of salt (sodium) in your diet. If you consume several grams of sodium a day, you could need 3 l of water each day. If your diet is very low in sodium, hardly any water besides what is in typical food is sufficient. However, I can't provide a cite.

In addition, if your diet is low in sodium, too much water can kill you. Google hyponatremia for sources.

[Rucksinator]

OK, perhaps I need to amend my 3rd sentence a little. The way I initially read the posts in the thread, it seemed like it was pointed out that you don’t need 8 glasses of water to survive (agreed), and then guinnog expressed relief that the idea that water is good for you had been debunked.* I thought that his(her) post was a bit of a non sequitor.

I’ll have to back out as I don’t have time to look for cites, and likely wouldn’t find any anyway.
Can we all agree that water = good, no water = bad, too much water = bad?
* I realize I’m being a bit disingenuous here.

Originally Posted by Tris

I met a guy once who would not drink water. Never. He believed that the stuff was bad for you, diluted you blood. He preferred beer. He was eighty years old, and working his third career. Obvious proof that water is bad for you. What "evidence" do you have to offer?

Where were you when I had a question about living off nothing but beer and sugarbuns?

[KarlGauss]

Drinking lots of water (i.e. fluids) may protect against the development of bladder cancer (reference).

A high fluid intake also seems to lessen the chance of getting kidney stones (reference <== look around 3/4 of the way down in the abstract)

[guinnog]

Originally Posted by Rucksinator

OK, perhaps I need to amend my 3rd sentence a little. The way I initially read the posts in the thread, it seemed like it was pointed out that you don’t need 8 glasses of water to survive (agreed), and then guinnog expressed relief that the idea that water is good for you had been debunked.* I thought that his(her) post was a bit of a non sequitor.

I’ll have to back out as I don’t have time to look for cites, and likely wouldn’t find any anyway.
Can we all agree that water = good, no water = bad, too much water = bad?
* I realize I’m being a bit disingenuous here.

LOL yes I can accept your formula.

It irritates me when people force-drink loads of water (especially expensive 'designer water') and act as if they were doing something good.

Unless you are thirsty, there is no need to drink. And water does you just as much good whether it is in fruit juice, coffee, soup, or beer. The whole detox thing is a bunch of baloney.

John

[Balthisar]

Originally Posted by guinnog

And water does you just as much good whether it is in fruit juice, coffee, soup, or beer.

Errr... some of these tend to dehydrate you. So maybe their water still functions for what the body needs, but only for a short time. You'll have to replace it with something less dessicating.

[guinnog]

Originally Posted by Balthisar

Errr... some of these tend to dehydrate you. So maybe their water still functions for what the body needs, but only for a short time. You'll have to replace it with something less dessicating.

And your body will let you know when it needs that. It uses a clever mechanism called 'feeling thirsty'. Unless you feel thirsty, there is no need to drink anything. All of the water molecules you take into your body are equivalent; your body knows nothing of whether it came as part of a glass of beer, orange juice, soup, solid food, or even metabolic water.

No health benefits will accrue from drinking more water than your body needs.

Phew. Thirsty work; think I'll have a beer.



John

[Eleusis]

Cecil says you don't need any water, if you eat six pounds of bread per day.