All the reasons watermelon is so good for you, plus how to pick out a perfectly ripe one at the supermarket.

By Cynthia Sass, MPH, RD
August 12, 2020
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Watermelon is a summertime staple, and truly one of the most beautiful, delicious, and fun fruits to enjoy. Fortunately it’s also incredibly good for you. Here are eight of watermelon’s important health benefits, how to pick a perfectly ripe fruit, and a few ways to incorporate water into meals, snacks, drinks, and desserts.

Watermelon keeps you hydrated

Water isn’t in this fruit’s name by chance. One cup of watermelon contains five ounces of water (about the size of a yogurt container). Consuming an adequate amount of fluid—including from water-rich foods—supports circulation, skin health, and digestion. It also helps regulate body temperature, organ and joint function, metabolism, appetite, and waste elimination.

Being properly hydrated also impacts mental performance. Research shows that as little as a 1-3% loss of body fluid can impair mood, reduce concentration, increase headaches and fatigue, interfere with working memory, and boost anxiety.

It boasts key nutrients and few calories 

Watermelon is lower in calories and sugar than you may think. One cup of watermelon provides 45 calories from 11 grams of carbohydrate, 9 grams of which are naturally occurring sugar. But that natural sweetness is bundled with vitamins A and C, which support immune function and skin health, in addition to smaller amounts of potassium, magnesium, B vitamins, and health-protective antioxidants.

Watermelon helps lower blood pressure and improve circulation

L-citrulline, a natural substance in watermelon (particularly in the white part of the rind), has been shown to improve artery function and lower blood pressure by helping blood vessels relax, which opens up circulation.

L-citrulline’s impact on blood flow is also the reason watermelon has been deemed “nature’s Viagra.” (Viagra eases erectile dysfunction by increasing blood flow in the penis.) Research also shows that L-citrulline may improve muscle oxygenation and athletic performance during endurance exercise.

It reduces muscle soreness

In one study, athletes who consumed 16 ounces of watermelon juice an hour before exercise experienced reduced muscle soreness and a quicker heart rate recovery compared to those who received a placebo drink.

Another study in male runners found that those who drank 16 ounces of watermelon juice enriched in L-citrulline two hours before performing half-marathon races had less perceived muscle soreness for up to 72 hours compared to those who downed a placebo beverage.

It can lead to healthy weight management

Watermelon may help support healthy weight management when it’s consumed in place of a processed sweet snack. A 2019 study from San Diego State University looked at satiety and weight changes after a four-week intervention in overweight and obese adults.

During the study, one group was asked to consume two cups of fresh watermelon daily, while a second group ate low-fat cookies that had the same number of calories as the watermelon. Participants were allowed to consume their respective snacks any time of day, during one or multiple sittings, or either alone or in combination with other foods.

Researchers found that watermelon promoted greater satiety than the cookies, and that satiety (diminished hunger, greater fullness, and a reduced desire to eat) lasted up to 90 minutes after eating. Additionally, the watermelon eaters lost weight, reduced their waist-to-hip ratios and blood pressure levels, and improved their antioxidant status and blood lipids.

Watermelon offers digestive support

While watermelon isn’t very high in fiber, the fiber it does contain supports healthy gut function. The fruit also contains fluid and prebiotics, a type of fiber that stimulates the growth and/or activity of beneficial bacteria in the large intestine. Prebiotics are tied to healthy immune function, anti-inflammation, and positive mood. Prebiotics also boost mineral absorption, improve blood glucose and insulin levels, and may protect against colon cancer.

It helps defend against disease

Watermelon is one of the best sources of lycopene, an antioxidant known to combat oxidative stress, which occurs when there is an imbalance between the production of cell-damaging free radicals and the body's ability to counter their harmful effects. The protection lycopene provides reduces the risk of chronic diseases, including heart disease, type 2 diabetes, and cancer, as well as neurodegenerative diseases like Alzheimer's. For the most lycopene, opt for traditional pink flesh watermelon, which packs much more of the antioxidant compared to yellow and orange varieties.

It may protect your skin 

If you’re a watermelon lover who takes full advantage of enjoying the fruit while it’s in season, it may offer some skin protection. Watermelon's vitamins A and C support healthy skin, and the fruit's lycopene content may protect against sun damage, although the effects are not immediate. One study found that the ingestion of tomato paste, which provided 16 mg lycopene, reduced sunburn after 10 weeks of daily consumption. According to the USDA, a cup and a half of watermelon contains about 9 to 13 milligrams of lycopene.

How to choose and store a ripe watermelon

The trick to choosing a ripe watermelon is to look for a yellow or cream-colored splotch or ground spot—the fruit’s key sign of peak ripeness. It should also feel heavy when you pick it up, since over 90% of a ripe watermelon is indeed water.  To retain the most antioxidants—up to a 139% difference, according to one study —store your watermelon at room temperature. Just be sure to wash the melon before you slice it, to prevent bacteria from being transferred from the surface to the edible fruit.

Ways to enjoy this delicious fruit

Fresh watermelon is amazing as is, but it can also be incorporated into both sweet and savory recipes. Combine cubes or watermelon balls with other fresh fruit in a simple fruit salad, garnished with fresh mint or a sprinkle of fresh grated ginger or shredded coconut. Add watermelon to a garden vegetable salad, or serve over fresh greens dressed with balsamic vinaigrette. Skewer watermelon and lime juice-coated avocado chunks for a colorful snack or appetizer, served raw or grilled.

Make a batch of watermelon salsa by combining the chopped fruit with cucumber, red onion, jalapeno, cilantro, and lime juice. Combine seedless watermelon with fresh lemon juice and freeze for a refreshing slushy drink. Or blend watermelon with coconut milk and chopped dark chocolate, then pour into popsicle molds for an alternative to icy treats made with added sugar. For a simple dessert, dip fresh watermelon cubes in melted dark chocolate—the two treats pair surprisingly well.

Cynthia Sass, MPH, RD, is Health's contributing nutrition editor, a New York Times best-selling author, and a private practice performance nutritionist who has consulted for five professional sports teams.

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