Truth Time: Do You Really Need 8 Glasses of Water a Day?

Hint: There’s water in your food, too.

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You’ve set a goal to drink more water (and less wine) this year. You even splurged on that fancy stainless steel water bottle everyone keeps talking about. The next step? Deciding how many times a day you actually need to refill that thing.

Upping your fluid intake (especially with plain H2O) has major health benefits. “Water is essential for survival and every cell, tissue, and organ in your body depends on it,” says Sharon Richter, RD, a nutritionist in New York City. Here are all the ways water can benefit your body.

You’ve likely heard the recommendation that eight glasses of water is the magic number for staying hydrated. On average, American adults don’t get anywhere near that, drinking about 39 ounces of water a day, according to the CDC. So are the majority of Americans chronically dehydrated?

Not necessarily. Drinking eight glasses of water probably won’t hurt you, but researchers have not been able to find scientific evidence that it’s necessary for good health either. “In general, healthy individuals actually need about four to six cups a day,” says Richter. FYI, that’s about 32 to 48 ounces.

Certain factors will affect your personal water consmption needs, according to Richter. For example, athletes or people who live in hot, sunny climates will need to drink more to replenish fluids lost from sweating.

Another important variable is your diet. Some foods naturally contain more water (the obvious example being watermelon) than others—and yes, this water in food counts toward your daily fluid intake. An estimated 20 to 30 percent of our fluid intake comes from food, according to a 2013 study from the ACSM’s Health & Fitness Journal. People who eat more water-rich foods, (fruits and veggies take the big prize here), may be just fine drinking fewer cups of water.

Skimping on the fluids puts you at risk of dehydration, which can become a more serious problem than just feeling thirsty. A 2007 article in the Annals of Epidemiology found that dehydration led to around 518,000 hospitalizations in one year, 88 percent of which were emergency or urgent care situations. Some early warning signs of dehydration are weakness, low blood pressure, dizziness, confusion, or a dark-colored urine. (Learn more here about what your pee color can reveal about your health.)

Shooting for a specific number of glasses of water a day might help motivate you (just like your Fitbit spurs you to log more steps), but your best bet might simply be to listen to your body. “When you feel thirsty, you’re probably close to dehydration, and you should really try to avoid this feeling,” says Richter. “Drink before you feel thirsty.”

Not a fan of plain water? Herbal tea or water infused with fruit are two waistline-friendly options. Try these recipes for a fruity, non-alcoholic “sangria” or soothing lemon ginger tea.