How Healthy Is Watermelon?

Watermelon is the fruit of summer. In the United States, it’s more popular than cantaloupe, honeydew and all other melons combined.

It’s good for your body, too, especially on a hot day. Here’s a rundown of watermelon’s healthiest qualities, plus some cool and delicious recipes from New York Times Cooking.

It’s hydrating.

“Watermelon” is a fitting name, because it’s more than 91 percent water. When you eat an average-size wedge (10 ounces or so), you’re effectively drinking a full cup of water.

Hydration keeps the body functioning as it should, from promoting blood flow to bowel regularity. The water in watermelon helps keep you hydrated, which can be extra beneficial in hot weather, when you lose more fluids through sweat.

“Our bodies recognize and utilize water molecules regardless of the source,” said Dr. Tamara Hew-Butler, a sports medicine scientist at Wayne State University. “Moist foods like fruit, vegetables and soups are considered water sources.”

Older people, in particular, may find it easier and more enjoyable to get some of their fluids through fruit, said Amy Ellis, a dietitian and associate professor of nutrition at the University of Alabama. They tend to feel less thirsty and therefore drink less — one of the reasons they’re at a higher risk for dehydration and heat-related illness during a heat wave.

It’s not as sugary as you might think.

Because watermelon is mostly water, it’s also low in calories — a one-cup serving has just 46.

“Some people think it’s sky-high in sugar because it tastes so sweet, but really it’s very moderate,” Dr. Ellis said. One cup of diced watermelon contains about 9.5 grams of sugar, which is less than the 13 grams in a cup of chopped apples or the nearly 15 grams in a cup of blueberries.

That’s little enough that the fruit likely won’t cause spikes in blood sugar, added Joanne Slavin, a dietitian and professor of food science and nutrition at the University of Minnesota.

Calories are energy, though, so watermelon alone won’t sufficiently fuel your body, said Samantha Dieras, a dietitian and the director of ambulatory nutrition services at Mount Sinai Hospital. But when you eat watermelon as part of a balanced diet, the water content and sweet flavor could help you feel satiated.

It’s heart healthy, to some degree.

Watermelon is fat- and sodium-free, which is good for your heart. But the jury is still out as to whether watermelon plays an active role in lowering heart disease risk, Dr. Slavin said.

Dr. Slavin, Dr. Ellis and Dr. Dieras all suggested that the amino acid L-citrulline and the micronutrient lycopene — both abundant in watermelon — could improve heart health. There’s a rationale for these ideas, Dr. Slavin said.

Scientists know that the kidneys convert L-citrulline into nitric oxide, which can relax your artery walls and lower blood pressure. And lycopene, a chemical found in certain plants, can reduce inflammation, which is linked to heart disease. People tend to associate lycopene with tomatoes, but watermelon has more.

Still, independently funded human studies directly examining watermelon’s effect on heart health have not shown measurable improvements. “Watermelon is not a magic bullet,” said Dr. Ellis, who led one of the studies. “It’s not going to displace blood pressure medication or anything like that. But if it’s incorporated into a diet with nutrient-dense foods, it may be a good thing for vascular health.”

Here’s how to make the most of it.

Watermelon doesn’t lend itself well to canning, drying or freezing, Dr. Slavin said, so it’s harder to enjoy out of season. She thinks this is one reason the fruit is so loved.

“Watermelon is summer and happiness,” she said. “When someone cuts open a fresh watermelon and hands you a hunk, that’s when it’s best.”

It’s also delicious in a dinner salad, soup or fizzy drink. Here are some recipes from NYT Cooking to get you started.

Recipe: Farro and Watermelon Salad

In this satisfying grain bowl, watermelon is paired with farro, cheese, herbs and red onion. You can substitute quicker-cooking rice or quinoa for the farro.

Recipe: Tomato-Watermelon Gazpacho With Avocado

Keep a pitcher of this chilled soup in the refrigerator for an instant meal on sweltering days. Watermelon tempers the sweetness of overripe summer tomatoes in the blended mix.

Recipe: Country Panzanella With Watermelon Dressing

Juicy with chunks of watermelon, tomatoes and cucumber, this ultimate summer salad becomes even more refreshing with a watermelon dressing. Toasted ciabatta and crumbled feta make it filling enough to be a meal.

Recipe: Watermelon Chaat

This savory fruit dish tossed with spicy cumin-citrus dressing could work with any fruit, but is especially good with watermelon. It’s tasty as a stand-alone snack or as a side dish.