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Your Morning Coffee Hydrates You Almost as Well as Water

Despite what haters say, chugging coffee isn’t drying you out

Coffee is a remarkable substance. It gives you energy. It makes you poop. It helps you disregard the crushing reality of capitalism so you can tolerate yet another day of unrelenting production at the hands of our billionaire overlords.

But coffee does have an alleged imperfection: Because it’s a diuretic, people say drinking too much of it can cause dehydration. Is that true, though, or just another form of coffee defamation

It depends on what kind of coffee you drink, but no, it’s not really true.

“Coffee in general is a very mild diuretic,” says Dana Hunnes, senior dietitian at the Ronald Reagan UCLA Medical Center. “It’s nearly as hydrating as water.”

If you don’t believe her, a 2014 scientific study concludes, “These data suggest that coffee, when consumed in moderation by caffeine habituated males, provides similar hydrating qualities to water.” And they define moderation as three to six cups a day (which is my kind of moderation).

As for the most hydrating type of coffee, there are a few things to consider: (1) More caffeine means more of a diuretic effect, and therefore less net hydration; and (2) more water in the final brew obviously means more hydration. “Espresso is less dehydrating,” says Jessi, a barista, since it contains less caffeine (in the ways we normally drink it) than brewed coffee. However, it also contains less water. “Drip and cold brew are more concentrated, therefore more caffeinated, which in turn would make them more dehydrating. Plus, with drip and cold brew, more quantity is typically consumed than with espresso drinks. Also, the milk fats in espresso drinks help release the caffeine into your system more slowly, as the milk coats your stomach.”

When you consider all of that, the most hydrating coffee is one with a low caffeine concentration and a high water concentration. “A black decaf iced coffee would be the most hydrating drink, but in general, [coffee] is a hydrating drink,” Hunnes says. An Americano — espresso and water — would also be a good bet, going by Jessi’s explanation of caffeine above.

But even if you’re not into decaf or Americanos, as long as you keep your consumption below five or six cups a day — the amount where that diuretic effect supposedly begins to take a significant toll — you can rest easy knowing that you’re staying hydrated enough. 

Welp, notch another victory for the hydro haters — the people who hate drinking water. Now get back to work before our billionaire overlords catch you reading this.