You don’t need eight glasses of water a day and other lies we believe
For decades, we’ve been told that to stay healthy it’s imperative that we drink at least eight glasses of water a day. It turns out that’s not actually true.
At some point in your life, someone probably told you that you should drink at least eight glasses of water a day for health reasons. It supposedly keeps you properly hydrated, which among other benefits helps your skin and leads to healthy kidney function.
It turns out that there is no proof of that, and there never has been.
It’s just one of those things that’s been repeated so many times that we’ve just come to accept it. Of course there must be a scientific reason, right? People have been saying it’s true for decades.
Yeah, not so much.
According to pediatrician Aaron E. Caroll, there is no research to back this up. Caroll recently wrote a book specifically debunking common health myths, including the eight glasses a day idea. With dehydration becoming an increasingly big issue among children though, Caroll took to the NY Times to pen a new op-ed restating the facts.
“Contrary to many stories you may hear, there’s no real scientific proof that, for otherwise healthy people, drinking extra water has any health benefits,” he stated. “For instance, reviews have failed to find that there’s any evidence that drinking more water keeps skin hydrated and makes it look healthier or wrinkle free.”
It’s not exactly clear where the eight glasses of water a day myth came from, but Science Alert traces it to a 1945 Food and Nutrition Board recommendation. Even then, it is often misunderstood or misquoted.
The line in question reads “a suitable allowance of water for adults is 2.5 litres daily in most instances. An ordinary standard for diverse persons is 1 millilitre for each calorie of food.” That equals out to be around eight glasses per day, but that volume may have even been arbitrary. There is nothing to back up that particular amount.
Most people also seem to ignore, or just not know the next part though.
“Most of this quantity is contained in prepared foods,” the recommendation reads.
Fruits and vegetables are packed with water. That means that as long as you eat foods that aren’t completely terrible for you, you should get at least some of your daily water through eating and you don’t need to force glass after glass of water down your throats, or the throats of your kids.
Another report from physician Heinz Valtin in 2002 also studied subject, and found that you don’t specifically need water to stay hydrated, other liquids are fine. That busts another myth of sorts. It turns out that certain liquids including diuretics like coffee, tea, and even alcohol don’t necessarily dehydrate us.
“This conclusion is supported by published studies showing that caffeinated drinks (and, to a lesser extent, mild alcoholic beverages like beer in moderation) may indeed be counted toward the daily total, as well as by the large body of published experiments that attest to the precision and effectiveness of the osmoregulatory system for maintaining water balance,” Valtin said.
It took me about 30 seconds to find an article on a health website claiming you need water over all other things, and to avoid coffee and tea. Caroll also debunked another watery myth.
“When your thirst mechanism kicks in, your body is signalling that you are already dehydrated,” the website linked above reads. This is not true.
Basically, we get thristy when we are, well, thirsty. That doesn’t necessarily mean we are dehydrated. We become thirsty “when the concentration of blood (an accurate indicator of our state of hydration) has risen by less than 2 percent,” he says, “whereas most experts would define dehydration as beginning when that concentration has risen by at least 5 percent.”
It turns out that milk may not be good for you either. So basically everything we know is a lie.
It’s not like you should avoid water or anything. It’s still good for you and all, it’s just that there is no official guideline to tell you how much to drink. If you’re thirsty, grab some water, or grab another fluid. If you are thirsty, don’t pass on something like coffee if there’s no water nearby.
Caroll still recommends water above other liquids, but he cautions people to avoid the hype.
“There is no formal recommendation for a daily amount of water people need. That amount obviously differs by what people eat, where they live, how big they are and what they are doing,” he writes. “But as people in this country live longer than ever before, and have arguably freer access to beverages than at almost any time in human history, it’s just not true that we’re all dehydrated.”