Water-Drinking Myths

There are so many myths out there about drinking water, it’s crazy! Like the good ol’ myth that you should drink 8, 8-ounce glasses of water per day (or 2 liters). Or the (relatively) new myth that you should drink half your body weight in ounces. Also not true. And the big, fat lie that drinking a single cup of coffee dehydrates you by the equivalent of 42 glasses of water.

Let’s tackle these one-by-one

 Myth #1: You Should Drink 8, 8-ounce Glasses (2 liters) of Water Per Day

 I actually covered this myth a couple years ago, in my article “how much water should you drink a day?”

The short version is this:

  • We all need different amounts of water
  • This myth actually refers to our need to get the equivalent of 2 liters of water per day. Since fruits and vegetables are over 50% water (and in some cases, over 90%), a lot of our water requirements are satisfied by these.
  • If your urine is clear, you’re well-hydrated. If your urine is really yellow (and you can’t attribute that to supplements or medications), then you’re likely under-hydrated)

If you want to read the full article, check it out here.

Myth #2: You Need to Drink Half Your Body Weight in Ounces 

This myth has it all: it’s scientific-sounding, because there’s a formula. It makes you really think hard about how much water you need. It gives you a warm, fuzzy feeling knowing there’s “science” behind the recommendation. Too bad that it’s pseudo-science. And it’s wrong.

It is an improvement over the blanket statement of “just drink 2 liters of water per day”, since it takes body weight into account, but it still doesn’t account for the other elements.

Again, does a person who exercises need the same amount as someone who doesn’t, even if they weigh the same? No. If we have two people of identical weight, and one sweats more than another, do they both need the same amount of water? No. If we have two people of the same weight, and one eats lots of fruits and veggies, and the other doesn’t, do they have the same water requirements? No again.

Be smarter than that. Don’t fall for this pseudo-scientific trap that unfortunately many nutritionists and natural health practitioners fall into. Just because it sounds scientific, don’t turn your logic off.

Myth #3: If You Drink Coffee, You Lose Water

This is another crazy one. I’ve read different figures, ranging from 6 to 42. That is if you drink one cup of coffee, you lose the equivalent of 6 to 42 glasses of water from your body.

This one must have been started by someone who doesn’t know math, physiology or has any logic.

Even without knowing any physiology, plug in your logic. If each glass contains 250 ml, 42 glasses would be 10.5 liters of water (or 10.5 kilos, or 23 pounds). At 6 glasses, that’s 1.5 liters (or 1.5 kilos or about 3.5 pounds). So let me ask you: last time you drank coffee, did you lose between 3.5 and 23 pounds over the next few hours?

If you lost that much every time you drank coffee, at 3.5 pounds, that would be a serious health concern, and at 23 pounds, you’d be dead.

Yes, coffee has a slight diuretic effect (and even then, not in everyone). So if you drink a cup of coffee, yes, you’re probably not getting the equivalent of 250 ml. You’re probably getting slightly less, but by no means are you losing water. 

Myth #4: It’s Better to be Overhydrated Than Dehydrated 

The myth goes that it’s better to be overhydrated than dehydrated. Why? Because any extra water, your kidneys will process that, and you’ll just pee it out. That’s only partially true.

Every once in a while, we hear of someone drinking so much water that they literally die. But we think to ourselves “that’s so rare that it doesn’t happen.” And maybe something that is taken that far is quite rare, but overhydration is quite common (although yes, dehydration is still much more common). Health enthusiasts hear myths such as the ones above (drink 2 liters of water per day, or drink half your body weight in ounces), and think that more is better. So they walk around with 4-liter jugs of water, trying to finish that in one day. Know anyone like that?

What’s wrong with that?

You have important chemicals in your blood and in your body, and the ratio of water to chemicals is very important. For example, you should have about 0.045-0.055 mmol/l of sugar in your blood (when fasting). You should have about 135-155 grams/l of hemoglobin (the protein that carries iron in the blood). Likewise, you should have about 135-145 mmol/l of sodium and 3.5-5.2 mmol/l of potassium.

But if you really dilute your blood, these values all drop. Your hemoglobin drops, your blood sugar drops, your sodium and potassium drop, and other things drop as well.

As a result, you feel confused, fuzzy-headed, maybe even dizzy or tired. Sound like the symptoms of dehydration as well? That’s right. The symptoms of dehydration and overhydration are quite similar.

So don’t think that you just can’t get enough water. You can definitely get too much, and the best amount is a happy medium.

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