Water myths

Make sure to breathe 17,280 times a day. It’s for the good of your health. Don’t forget to take those breaths or your health will suffer.


OK, there’s no guidance yet on how much air you should breathe. Maybe that’s just because nobody has worked out how to sell air yet. Not so for water. How many times have you heard that you should drink x amount of water a day? You might have even heard that tea, coffee, soft drinks, beer and wine somehow don’t count as containing water. It’s not just the Penelope Keiths either. Even the respectable and respected nutrition advisers seem to give out this tosh. The Food Standards Agency, for instance, presents a sanitised version of the “other drinks may not count” argument.

The British Nutrition Foundation cites unspecified authorities to recommend an amount. More crucially, it says thirst doesn’t tell you when you need water.

Health professionals recommend at least 1.5 to 2 litres (6-8 cups) of liquids a day in temperate climates. The sensation of thirst is not triggered until there is already a water deficit, so it is important to drink before you get thirsty.

So, it’s pleasant to see a public debunking of the “drink 2 litres of water a day myth”. A Penn U study showed that there was no health benefit to drinking extra water.

You don’t get much more of an insistent human drive than thirst. So why do we have so many “experts” telling us that thirst isn’t a good guide to needing water? We may be bad at letting our hunger tell us when to eat. But thirst is pretty basic.

There are a very few circumstances (e.g. heat stroke if you’ve suddenly moved from winter Finland to summer Malaysia) in which your own thirst isn’t a good guide to how much you should drink.

(In any case, I wonder how anyone could drink as little as 2 litres of water-based fluid a day. I’ve had that before lunchtime, if coffee counts.)

4 thoughts on “Water myths

  1. Ironically, I went to see the doctor today about a sore foot and was quizzed to ensure I actually consume “8 drinks of water” a day. When I asked if mouthfuls counted as separate ones the Dr didn’t seem to see the funny side of it. 😳

  2. Actually, there are situations where thirst is NOT an adequate guide. I’m a geology student, and have taken several trips to Southern California deserts in the cool season. It isn’t hot, one doesn’t tend to sweat simply hiking about and looking at rocks, and one doesn’t tend to feel thirsty. Yet the air is very dry, and it is easy to get dehydrated.

    But 2 liters of water in less hostile climates is silly. Mind you, I drink far more than 2 liters of liquids every day, but most of that is coffee, tea, or soda.

  3. Karen
    Thanks for the comment.
    If it’s very dry, your sweat will evaporate very quickly so you mightn’t realise that you are sweating a lot so this might be an acclimatisation thing that’s harder to recognise than in a humid hot place.

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