Watermelon Nutrition Facts and Health Benefits

Watermelon annotation

Verywell / Alexandra Shytsman 

Watermelon, one of summer's most iconic fruits, is low in calories and rich in water. Watermelon is often eaten on its own as a sweet snack (think: every picnic and BBQ of the season), but it can be a versatile ingredient in many recipes. It's also an excellent source of lycopene and vitamins A and C and is less acidic than citrus fruits and tomatoes, other well-known providers of lycopene and vitamin C.

Native to tropical Africa, watermelons are grown commercially in the U.S. in areas such as Texas, Florida, Georgia, and California where the weather is warm and conducive to a long growing season.

Watermelons have a thick rind and range from solid green, green striped, or mottled with white. They can be round or oval in shape and weigh as much as 30 pounds. The crisp flesh is mostly pinkish-red, although golden-fleshed varieties are becoming more popular. Watermelons have small, hard, black seeds throughout, with seedless hybrids available.

Watermelon Nutrition Facts

The following nutrition information is provided by the USDA for 1 cup (154g) of raw, balled watermelon.

  • Calories: 46
  • Fat: 0.2g
  • Sodium: 1.5mg
  • Carbohydrates: 11.6g
  • Fiber: 0.6g
  • Sugars: 9.5g
  • Protein: 0.9g
  • Vitamin C: 12.5mg

Carbs

The carbohydrates in watermelon are mostly sugars, with only a little fiber. If you are counting carbohydrates, it's best to measure watermelon carefully.

  • 1 cup diced watermelon (152g): 0.6 grams fiber, 9.4 grams sugars, 11.5 grams total carbohydrates, 10.9 grams net carbohydrates
  • 1 medium-sized wedge of watermelon (286g): 1.1 grams fiber, 18 grams sugars, 22 grams total carbohydrates, 21 grams net carbohydrates

Half of the sugar in watermelon is fructose, one quarter is glucose, and less than one quarter is sucrose, with other sugars making up minor fractions.

Watermelon has an average glycemic index of 76, which ranks it as high. This means it could give you a faster rise in blood sugar than foods of a lower glycemic index. Watermelon looks better when considering glycemic load, which takes into account how much you eat per serving. A glycemic load under 10 is considered low. A wedge of watermelon has a glycemic load of 6, while half a cup of chopped watermelon is 1.5.

Fats

You will get almost no fat in watermelon, making it similar to other melons such as cantaloupe or honeydew. The fat that is present is evenly split between saturated, monosaturated, and polyunsaturated fat. For dietary tracking purposes, you can consider watermelon a non-fat food. If you concentrate the seeds (yes, they are edible), they are a source of omega-3 fatty acids.

Protein

Watermelon has only a little protein, with just under 1 gram (g) per 1 cup serving. Interestingly, some companies are producing watermelon seed protein by sprouting and shelling the seeds. You won't be able to get that level of protein from fresh seeds, however, because the shell of the seed prevents digesting the protein inside.

Vitamins and Minerals

A fully ripe red watermelon contains higher levels of nutrients than less-ripe pink watermelon. A single serving of watermelon is a good source of vitamin C and vitamin A, providing a significant percentage of your daily requirement for each.

Vitamin C can aid in wound healing and is said to have anti-aging and immune-boosting properties, whereas vitamin A is important for eye health. A one-cup serving of watermelon also provides about 7% of your daily needs of copper and pantothenic acid, 5% of biotin, and 4% of vitamins B1 and B6.

Health Benefits

Beyond just being a sweet summer treat, watermelon can boost your health in several ways.

Fights Dehydration

Aptly named watermelon is 92% water, making it a very hydrating food choice. If you or your children struggle to drink enough water, especially on hot summer days, try a few servings of watermelon. You'll get extra micronutrients along with your hydration.

Delivers Antioxidants

Watermelon has antioxidant power because it is an excellent source of lycopene, a carotenoid phytonutrient that research has shown may help reduce or prevent high blood pressure. Lycopene is well-known for being present in tomatoes, but a fully-ripe watermelon has even more lycopene than tomato.

Other antioxidants in watermelon include flavonoids, carotenoids, and triterpenoids. Antioxidants assist in cell repair and may help lower your risk of infections and some cancers.

Contributes to Weight Loss

In a small study of overweight adults, those who consumed watermelon vs. low-fat cookies felt more full and showed reductions in body weight, body-mass index, and blood pressure.

Helps Ease Muscle Fatigue

The amino acid citrulline is present in significant amounts in watermelon. You can find capsules of concentrated citrulline sold as a nutritional supplement for sports performance. The benefits of citrulline are not conclusive, although there are studies that show citrulline supplements might reduce the feeling of fatigue during exercise. 

Allergies

Watermelon food allergies are rare. However, if you have hay fever, you may have a pollen-allergy food syndrome which may lead to a cross-reaction to the proteins in watermelon that are similar to the pollen. If you are allergic to ragweed pollen or grasses, you may experience a similar reaction when you eat watermelon.

You might feel a tingling or itch in your mouth after eating watermelon. In rare cases, this can be more serious and trigger throat swelling or anaphylaxis.

Adverse Effects

Watermelon, consumed in moderation, poses few risks. Because it does contain sugar, people with diabetes will need to be cautious when eating watermelon.

Varieties

Watermelon comes in dozens of varieties and cultivars. These can be grouped by size ("icebox," or smaller varieties, vs. larger "picnic" types), color of flesh (pink, yellow, orange), and seeded vs. seedless.

When It's Best

Watermelon is in season in summer in the U.S. A ripe watermelon is one that feels heavy for its size. The outside should be firm and free of nicks or dents. The ground spot—where the melon was resting on the ground—should be a creamy yellow color, as opposed to white.

Storage and Food Safety

Fresh, uncut watermelon can be stored at room temperature. Heat will cause the flesh to dry out, so if it's hot, watermelons should be kept in a cool place or in the refrigerator, if available. Uncut watermelon can be stored in the refrigerator for two to three weeks.

Once you cut watermelon, you can keep it in the fridge for up to five days if it is in a closed container or sealed plastic bag. You can also freeze watermelon that's been cut up into chunks.

How to Prepare

Go beyond typical slices and add watermelon to smoothies, salsa, and salads (both fruit salads and veggie-heavy ones, too). Its subtle sweetness also pairs well with cheese, nuts, and other protein sources. You can also grill or freeze watermelon for a tasty dessert. Place cold or frozen watermelon chunks into water or seltzer for a tasty, low-calorie beverage.

The whole watermelon is edible. You can eat the seeds as well as the rind. (The white seeds in a seedless watermelon are actually empty seed coats that did not fully mature.) Rinds can be stir-fried, stewed, or pickled.

Recipes

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