Watermelon Nutrition Facts

Calories, Carbs, and Health Benefits

Plate of watermelon popsicles
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Watermelon is a refreshing fruit that is low in calories and rich in water (92 percent). It is often eaten on its own as a sweet snack, but it can be a versatile ingredient in any meal plan. 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 30 pounds at times. The flesh is mostly pinkish-red is crisp, although golden-fleshed varieties are becoming more popular. Watermelons have small, hard, black seeds throughout, with seedless hybrids available.

Nutrition Facts

Watermelon Nutrition Facts
Serving Size 1 cup, balls (154 g)
Per Serving% Daily Value*
Calories 46 
Calories from Fat 2 
Total Fat 0.2g0%
Saturated Fat 0.1g1%
Polyunsaturated Fat 0.1g 
Monounsaturated Fat 0.1g 
Cholesterol 0mg0%
Sodium 2mg0%
Potassium 171.21mg5%
Carbohydrates 11.6g4%
Dietary Fiber 0.6g2%
Sugars 9.5g 
Protein 0.9g 
Vitamin A 18% · Vitamin C 21%
Calcium 1% · Iron 2%
*Based on a 2,000 calorie diet

Watermelon is low in calories (only 46 in one cup) and rich in water content, making it a very hydrating food choice.

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 or balled watermelon: 0.6 grams fiber, 9.5 grams sugars, 11.6 grams total carbohydrates, 11 grams net carbohydrates
  • 1 wedge of watermelon (1/16 of a watermelon): 1.1 grams fiber, 18 grams sugars, 22 grams total carbohydrates, 21 grams net carbohydrates (also has 86 calories)

    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, and in this, it is similar to other melons such as cantaloupe or honeydew. The fat that is present is evenly split between saturated, monosaturated, and polyunsaturated fat. For any dietary tracking purposes, you can consider watermelon a non-fat food. If you concentrate the seeds, they are a source of omega-3 fatty acids.

    Protein

    Watermelon has only a little protein, with just under 1 gram 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.

    Micronutrients

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

    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 1 cup serving provides about 7 percent of daily needs of copper and pantothenic acid, 5 percent of biotin, and 4 percent of vitamin B1 and B6, which makes it a good source of each.

    Health Benefits

    Watermelon has antioxidant power because it is an excellent source of lycopene, a carotenoid phytonutrient which research has shown to be possibly effective for high blood pressure. Lycopene is well-known for being present in tomatoes, but a fully-ripe watermelon has even more lycopene. Other antioxidants you will find in watermelon include flavonoids, carotenoids, and triterpenoids.

    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.

    Common Questions

    What are the white seeds in a seedless watermelon? 

    The white seeds in a seedless watermelon are actually empty seed coats that did not fully mature. They are perfectly safe to eat.

    Can you eat the rind and seeds of a watermelon?

    The whole watermelon is edible. You can even eat the black seeds as well as the rind. Rinds can be stir-fried, stewed, or pickled.

    How can you tell a watermelon is ripe? 

    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.

    Should you refrigerate a watermelon or store it at room temperature? 

    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.

    Recipes and Preparation Tips

    Besides being eaten fresh on its own, watermelon is a great addition to smoothies, salsa, and salads. Its subtle sweetness also pairs well with cheese, nuts, and other protein sources. Freeze watermelon for a tasty dessert or place watermelon chunks into water or seltzer for a tasty, low-calorie beverage.

    • Watermelon Smoothie: This refreshing smoothie (#2 on the list) is great for breakfast.
    • Watermelon Cucumber Pico de Gallo: This salsa pairs cool watermelon and mint with jalapenos for a nice kick. It's a perfect condiment for fish, chicken, pork, or grilled vegetables.

    Allergies and Interactions

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

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