We've all read the health advice, run in endless magazines, newspaper articles, spouted on the radio and telly, told at dinner parties and down the pub; spread like a Christmas Cold, the received wisdom that you should drink eight glasses of water a day to remain fit and youthful.

It's bollocks of course. For starters, how big is a glass? I have shot glasses that will hold 12ml in my house, and a stein that will take two litres. I have every hope of getting a yard of ale for Christmas this year, and that's more than a quart. Which should I be drinking eight of?

There's also the fact that you should get half of your required daily moisture from your food. That, of course, assumes that your daily food doesn't consist entirely of crisps and chocolate. Even a takeaway burger has substantial amounts of liquid in it.

So what? I hear you ask. Water's pretty much harmless, how can it hurt to have too much? Well, it's possible to kill yourself from drinking too much water, although it takes quite a lot of trying. More easily, you can upset your salt balance, leading to headaches remarkably similar to those brought on by dehydration, and likewise sluggishness. And of course, constant drinking of water and the corresponding inevitable multiple trips to the toilet will wash out water soluble vitamins from any food you might have eaten before you can fully digest and make use of them.

Why am I bothered about this? Well there are many reasons. For one, it's yet another example of the message being dumbed down to the point where it is pretty much meaningless simply because our various media don't think people are bright enough to understand a concept with more than one syllable in it. For another it's just plain wrong and I don't like things that are plain wrong. But most of all I'm bothered by it because of the notice blu-tacked to the wall in the kitchen at work.

You can click on the image to embiggen it if you want, but the key point to take from this nonsense - apart from the sheer inventiveness of civil servants when it comes to wasting taxpayers' money - is the line which reads thus:

A 13 stone person should drink a full gallon a day.

What the fuck? A gallon? And that's not a sensible US gallon.* No, that's a UK gallon. Eight twenty fluid ounce pints. In a day. Every day. On top of any coffee and juice you might have for breakfast, any tea you might have around four in the afternoon.** In addition to that beer you might have with your evening meal, or the dozen down the pub with your mates.

A whole gallon of water. You'd need a catheter shoved up your jap's eye and a large bucket under the desk. Or seriously baggy incontinence pants. Otherwise you'd never get any work done. It would be sip... sip... ahhh, excuse me, I have to go see a man about a horse... All bloody day long.

I have a mangled old plastic water bottle on my desk that holds 750ml when full. During the course of an eight hour working day I'll maybe fill it once, though more often than not it's not empty by the end of the day. That and a mid-morning coffee*** are all the liquid intake I can manage. I'll have coffee and fruit juice at breakfast, milk on my corn flakes, and come the evening I'll have either water, beer or wine with supper depending on whether or not I've been good all week, but add it all up and it still comes short of a gallon.

On those occasional days when I drink more water - perhaps as much as a litre and a half between half eight and half four - I almost always feel more thirsty rather than sated. My mouth and throat go dry, as if all the saliva has been washed away by something. And then there's that electrolyte imbalance headache.

My Dad was very amused by a poster he saw in the dunny at a gliding club in Australia a few years back. It was basically a colour chart, much like those you see in the paint aisles in DIY superstores. There were various shades, ranging from Irn Bru through to Buxton, and the simple question: what colour is your pee, mate?

For a glider pilot, especially in Australia where you can go vast distances and land out a long way from rescue, being well-hydrated is very important. Lack of sufficient fluids can lead to potentially fatal loss of concentration when you're twenty-thousand feet up and rising fast in a thermal. But as those canny Aussies know, it's not about drinking a gallon of water a day, regardless of how you feel. It's about understanding how your body works and recognising the signs it gives you.

So forget your eight glasses, your yard of ale, or whatever measure you've been told. If your pee is still the colour of roadside cafe coffee**** at midday, then you're not getting enough water. If it's running clear as a mountain stream, then you've probably had enough.

* Someone, someday will explain to me why it is that a UK pint is twenty fluid ounces. 'A pint of fresh water weighs a pound and a quarter' as the saying goes. But why? Surely a pint of water should weigh a pound. A litre of water weighs a kilo, after all. I don't often think the Americans have got it right, and when it comes to beer that extra 25% is certainly welcome, but the sixteen fluid ounce pint makes sense when you have a sixteen ounce pound. Of course, a fourteen pound stone makes no sense at all.
** with cucumber sandwiches, made from white bread with the crusts cut off.
*** decaf, preferably beans that have undergone the Swiss Water process. Mostly I get my stuff from Steve at Hasbean, and this is a plug for him.
****it's a mystery of the British cafe, that if you order a mug of tea it will be as black as the devil's unmentionables, but if you order coffee you'll still be able to read the letters on the bottom of the cup. Shouldn't it be the other way around?


norby said…
There are doctors who are now saying that the eight glasses of water a day is bad advice. Even if you drink nothing else, it's way too much water, and like you say, who can drink that much in one day?
John R said…
It's a famous myth based largely on a book called "Your Body's Many Cries For Water". As a rough actual guide (which is largely meaningless since your need for water is based on a million things - weight, exercise, ambient temperature, etc.) you need something like a litre or two a day, but most of that comes through your food (which is, of course, mostly water unless you munch nothing but crisps).

IIRC, US Army health advice says that no one should drink more than a (US) gallon per day due to the risks of hyponatremia. (I've wondered in the years since it happened whether or not a seizure I had was due largely to that. I'd been out on the piss the night before, eaten nothing the next day thanks to my hangover and drank 7 pints or so of diet coke with a mate in the afternoon before England played Portugal in Euro 04. Had muscle spasms, blacked out and woke up in A&E. So if that was down to hyponatremia, it doesn't take a great deal to do it.)

The advice gets spouted everywhere, but like you say, it's utter bollocks.
swallowtail said…
Watch a dog, or cat, or any animal... they drink water. We humans keep their bowls clean and full, and they drink as much as they need, which varies with exercise, climate, dinner, etc etc. Seriously, that is about as simple or complex, as the issue needs to be. H2O is required for the mammilian creatures to survive. Think of the brainpower and resources it took to create the "health" poster! Better said would be: Run! Play! Laugh! at regular intervals, all day long.
Great Post!
Has Bean Steve said…
Thanks for the plug James O Very kind :) Great blog by the way very cool.
JamesO said…
No problem, Steve. If you didn't supply very tasty coffee at very reasonable prices in a quick and efficient manner, I'd not bother plugging your site, but since you do, I will.

SW - I like that advice. I think I'll make up a spoof health poster for the kitchen, branded like this one, and stick it up just before I leave at the end of February. Run! Play! Laugh! What would the Welsh Assembly Government do?

John, that's diet coke for you. Disgusting stuff. Mind you if you'd been eating salty crisps as well, you'd probably have been all right. Not for nothing do desert explorers take salt pills as well as water with them.

Norby, I think the consensus is coming round to a less simplistic message now, but that poster is still up in the kitchen at work.
Gabriele C. said…
You don't need to drink that much water in Wales since you take up enough of it via the skin, with all that rain. :)

I'm in the upper range when it comes to the average daily amount of liquid intake (and most of it water and tea) but I know what my body needs; I don't keep lists and count litres.

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