Veggies and fruits, such as tomatoes, provide nutrients and water.
You’ve no doubt heard the advice to drink at least eight 8-ounce glasses of water each day. But do you know where that advice for avoiding dehydration comes from, and if you should still follow it?
Sean Hashmi, MD, the regional physician director of weight management and clinical nutrition for Kaiser Permanente in Southern California, says it dates back to a 1945 recommendation from the U.S. Food and Nutrition Board. “But people misread the statement,” says Dr. Hashmi, adding that some of the water you get comes from food.
That said, you still need to drink water during the day to avoid health risks. According to a January 2019 article published in Nutrients, proper hydration is important for maintaining cognition, reducing the risk of kidney stones, and managing weight. The National Academies of Science, Engineering, and Medicine (formerly the Institute of Medicine) suggests that women who consume about 2.7 liters of water per day and men who consume about 3.7 liters per day (as fluid and from food) are considered properly hydrated.
The exact amount you need also depends on factors including age, gender, activity level, pregnancy, and breastfeeding status, says Rachel Lustgarten, a registered dietitian with Weill Cornell Medicine in New York City.
The good news for those who have a hard time sipping H2O all day: The foods you eat play a big role in keeping you hydrated. Shreela Sharma, an associate professor and registered dietitian at UTHealth School of Public Health in Houston, estimates about 20 percent of the body’s hydration needs come from foods. “These foods are not just hydrating but also nutritious and provide various nutrients, including vitamins and fiber,” she says.
Another plus: You don’t have to overthink it. “If you are eating a diet rich in fruit and vegetables, this should not be hard,” says Julie Devinsky, RD, who is in private practice in New York City and is an outpatient nutritionist at New York Presbyterian’s Digestive Disease Clinic. To hit the mark, you can follow tried-and-true nutrition advice by aiming for two to three servings of fruit and five or more servings of veggies daily.
That said, some foods are more hydrating than others. “Foods that rehydrate are typically the ones that hold the most water,” says Garth Graham, MD, MPH, a Hartford, Connecticut–based cardiologist, and director and global head of healthcare and public health partnerships for YouTube and Google Health.
Just keep in mind that the fruit or veggie will lose water if it’s cooked. “To optimize the hydration aspect of these foods, it’s best to eat them raw or minimally cooked,” Devinsky says. And for the best, most hydrating effect, enjoy these foods with a glass of water. “As much as it is important to eat your daily dose of fruit and vegetables, don't use it as an excuse to skimp on water,” she adds.
Here are eight of the most hydrating foods and some ideas for how to enjoy them.