December 6, 2023

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Explore how watermelon can be a valuable addition to a diet

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Watermelon is a delicious and refreshing fruit that many people enjoy during the summer. It is a good source of vitamins A and C and lycopene. Watermelon also has a lower acidity level than citrus fruits and tomatoes, two other foods rich in lycopene and vitamin C.

However, if you’re conscious about your calorie intake or following a specific diet plan, such as those offered by Noom, you might be wondering how many calories are in watermelon.

In this article, we will explore the calorie content of watermelon and delve into its nutritional profile.

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How Many Calories Are in Watermelon: Nutrition Facts

The watermelon, as the name implies, is mostly made up of 91% water and some carbohydrates at 7.5%. So, how many calories are in watermelon? The number of calories in watermelon depends on the serving size.

  • 1 cup : 46
  • 1 wedge (286 grams): 86
  • 1/2 cup (76 grams): 23
  • 100 grams: 30

Now that you know how many calories are in watermelon, let’s explore its nutritional content.

In 100 g or 2/3 cups, watermelon has the following nutrient composition: [1]

  • Sugar: 6.2 g
  • Water: 91%
  • Protein: 0.6 g
  • Calories: 30
  • Carbs: 7.6 g
  • Fat: 0.2 g
  • Fiber: 0.4 g


Watermelon is mainly composed of sugars, with fructose being the dominant sugar followed by glucose and a small amount of sucrose. Fiber content in watermelon is low [1].

For carbohydrate monitoring, careful measurement is necessary. For example, 1 cup of diced watermelon (152 g) contains 0.6 g fiber, 9.4 g sugars, 11.5 g total carbohydrates, and 10.9 g net carbohydrates. A mid-sized wedge of watermelon (286 g) contains 1.1 g fiber, 17.7 g sugar, 21.6 g carbohydrates, and 21 g net carbohydrates.

Watermelon has a glycemic index (GI) of 76.2, indicating a relatively faster blood sugar spike. However, a half cup of diced watermelon has a low glycemic impact with a glycemic load of 4, considering the serving size [2].

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There are about 0.4 grams of fiber in a 2/3 cup (100 g) serving of watermelon, making it a poor source of this nutrient. On the other hand, since it contains fructose, it has a high level of FODMAPs, which are fermentable oligosaccharides, disaccharides, monosaccharides and polyols [2].

People who can’t completely digest fructose, such as those who have fructose malabsorption, may have unpleasant digestive symptoms when they consume large quantities of sugar [3].


Watermelon is a low-fat fruit with minimal fat content, including polyunsaturated, monounsaturated, and saturated fatty acids. It can be considered a non-fat item in your diet. Watermelon seeds are also edible and provide omega-3 fatty acids.


Watermelon has low protein content, with less than 1 gram of protein in one cup. While some industries extract protein from sprouted and shelled watermelon seeds, the protein content in fresh seeds is hindered by the seed shell and is not significant.

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Vitamins and Minerals

The vitamin C content of watermelon is high, and it also provides a sufficient amount of several other vitamins and minerals, including:

  • Vitamin B5. This vitamin, also known as pantothenic acid, may be found in some quantity in almost all types of food.
  • Vitamin C. This vitamin is necessary for proper immune function [4,5].
  • Potassium. This mineral is essential for maintaining healthy blood pressure and cardiac function [6].
  • Copper. The Western diet is notoriously deficient in this mineral, which is found in the highest concentration of plant foods [7].
  • Vitamin A. Beta-carotene is found in watermelon, and your body can convert this substance into vitamin A.

Watermelon Calories

How many calories are in watermelon? There are around 46 calories in one cup of watermelon sliced or balled. That said, if you would rather have it cut into wedges, you may be wondering how many calories are in watermelon wedges. There’s roughly one-sixteenth of the melon (286 grams) and has nearly twice as many calories, which comes out to around 86.

How Many Calories Are in Watermelon: Other Plant Compounds

Watermelon is not a particularly rich source of antioxidants compared to other fruits like apples, grapes, avocados and more. On the other hand, it has a high concentration of the amino acid citrulline and the antioxidant lycopene, all of which have various positive effects on health [8].

You can learn more about the amount of calories in an apple or get the answer to how many calories in grapes to know their nutritional value and make informed choices when incorporating them into your diet. Plus, you may read our review on the amount of calories in an avocado.


Lycopene is a potent antioxidant that gives fruits and vegetables their red color. Watermelon is the best recognized fresh source of lycopene [9,10, 11,12]. Fresh watermelon has a higher lycopene content per serving than tomatoes [13].

Based on human studies, drinking fresh watermelon juice is an excellent way to increase levels of lycopene and beta-carotene in the blood [14]. To a lesser degree, lycopene is also used to form beta-carotene, which is turned into vitamin A.

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Citrulline, an essential amino acid, is found in the highest concentration in watermelon of any food known to science. The greatest concentration is found in the white rind that encircles and protects the fruit’s flesh. [15,16].

The amino acid is metabolized and converted into arginine by our body. Both citrulline and arginine are essential for producing nitric oxide, which relaxes and dilates blood vessels to reduce blood pressure [17].

Summary: Watermelon Calories

How many calories are in watermelon? A cup of watermelon has approximately 46 calories and is low in fat. While it offers beneficial nutrients like vitamins A and C, it is relatively high in sugar. Therefore, individuals mindful of their sugar intake should consume watermelon in moderation.

How Many Calories Are in Watermelon?

The calorie content of watermelon varies depending on the serving size. So, how many calories are in watermelon based on different serving sizes?

How Many Calories Are in a Whole Watermelon?

Even if you eat a whole watermelon, you won’t even meet your daily calorie intake. So, how many calories are in a whole watermelon? According to FoodData Central of the United States Department of Agriculture (USDA), there are 1,360 calories in a whole watermelon that is 15 inches in length and 7.5 inches in diameter [18].

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How Many Calories Are in a Slice of Watermelon?

If you prefer slicing watermelon, you may be curious about how many calories are in watermelon slices. A single slice of watermelon (1/16 of a whole, measuring 15 inches by 7.5 inches) contains 86 calories.

Other calorie values provided by the USDA include 71 calories in 1 cup of watermelon juice, 46 calories in 1 cup of balled or diced watermelon, and 30 calories per 100g.

Incorporating watermelon into your diet can offer various health benefits, whether you cook homemade dishes or order nutritious diet meals from Noom. A slice of watermelon (86 calories) can provide percentages of daily vitamins and minerals, including [19]:

  • 25% of vitamin C for immune health and skin quality.
  • 30% of vitamin A for eye health and immune support.
  • 4% of iron for treating anemia and reducing tiredness
  • 2% of calcium for strong bones.
  • 8% of potassium for blood pressure control and hydration, and 4% of fiber for prolonged satiety.

How Many Calories Are in a Cup of Watermelon?

There are about 46 calories in a cup (152 grams) of diced or balled watermelon. But how many calories are in a cup of watermelon if you prefer to eat it wedged instead? A wedge that is around one-sixteenth of the melon (286 grams) contains almost double that amount or approximately 86 calories.

Health Benefits

In addition to knowing how many calories are in a watermelon, it is also crucial to understand its distinct health benefits.

Fights Dehydration

Because it contains about 92% water, eating (or drinking) watermelon is an excellent way to stay hydrated. It’s also a good source of electrolytes, which help balance hydration in the body.

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Reduces Blood Pressure

Lycopene is a carotenoid that may help promote normal blood pressure, and watermelon just happens to have lots of it. Although tomatoes are well recognized as a source of lycopene, a watermelon that has reached its full maturity has significantly more lycopene than a tomato does.

Contributes to Weight Loss

Watermelon can be a beneficial addition to a weight loss regimen. It is low in calories and high in water content, which can help you feel full and satisfied while consuming fewer calories overall. Additionally, watermelon is rich in fiber, which aids digestion and promotes feelings of fullness.

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Adverse Effects

Watermelon contains sugar, so those with diabetes should exercise caution while consuming watermelon to prevent blood sugar spikes.

Watermelon Varieties

Watermelons come in many varieties classified by size (icebox or picnic), flesh color (pink, yellow, or orange), and seed presence.

The calorie content of different varieties of watermelon varies slightly, but they are all relatively low in calories. So, how many calories are in watermelon varieties?

  • Crimson Sweet: 30
  • Sugar Baby: 38
  • Yellow Watermelon: 38
  • Black Diamond: 31
  • Jubilee: 40
  • Charleston Gray: 35
  • Horned Melon: 21

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How To Prepare Watermelons

You can do more with watermelon than just cut it into pieces; try adding it to different salsa recipes, smoothies and salads. Its mild sweetness works nicely with savory foods like cheese and almonds, as well as other sources of protein. You may also make a delicious dessert by grilling watermelon or freezing it.

Add watermelon chunks that have been refrigerated or frozen to water or seltzer for a refreshing drink that is low in calories. It is possible to consume every part of the watermelon. You can eat both the seeds and the rind of a watermelon.

The rind is often ground into flour and used in baking, and it may also be served as a side dish after being pickled, stewed or stir-fried.

Fun fact: The empty seed coats that seem white in a seedless watermelon are really immature seed coats that did not develop to maturity.

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The Bottom Line

Watermelon is a fruit that is incredibly good for your health and taste buds. It’s rich in citrulline and lycopene, two potent plant nutrients. These compounds have been associated with reduced blood pressure, enhanced metabolic health, and less muscular soreness after exercise.

So, how many calories are in watermelon? A cup of watermelon only contains about 46 calories, which is much lower than most other fruits and vegetables. By being aware of its calorie content, you can make informed choices about this refreshing fruit, especially if you’re following weight loss programs like Noom.

Next time you enjoy a juicy slice of watermelon, you can do so with the confidence that it fits into your dietary goals. Stay hydrated and make healthy choices with the delightful addition of watermelon to your diet!

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  2. Catassi, Giulia, et al. “The Low Fodmap Diet: Many Question Marks for a Catchy Acronym.” Nutrients, MDPI, 16 Mar. 2017,
  3. Kim, Young, and Chang Hwan Choi. “Role of Fructose Malabsorption in Patients with Irritable Bowel Syndrome.” Journal of Neurogastroenterology and Motility, Korean Society of Neurogastroenterology and Motility, 30 Apr. 2018,
  4. Hemilä, Harri, and Elizabeth Chalker. “Vitamin C for Preventing and Treating the Common Cold.” The Cochrane Database of Systematic Reviews, John Wiley & Sons, Ltd, 31 Jan. 2013,
  5. Telang, Pumori Saokar. “Vitamin C in Dermatology.” Indian Dermatology Online Journal, Medknow Publications & Media Pvt Ltd, Apr. 2013,
  6. CM;, Weaver. “Potassium and Health.” Advances in Nutrition (Bethesda, Md.), U.S. National Library of Medicine,
  7. Klevay, Leslie M. “Is the Western Diet Adequate in Copper?” Journal of Trace Elements in Medicine and Biology : Organ of the Society for Minerals and Trace Elements (GMS), U.S. National Library of Medicine, Dec. 2011,
  8. Tarazona-Díaz, Martha Patricia, et al. “Bioactive Compounds from Flesh and by-Product of Fresh-Cut Watermelon Cultivars.” Journal of the Science of Food and Agriculture, U.S. National Library of Medicine, 30 Mar. 2011,
  9. Di Mascio, P, et al. “Lycopene as the Most Efficient Biological Carotenoid Singlet Oxygen Quencher.” Archives of Biochemistry and Biophysics, U.S. National Library of Medicine, 1 Nov. 1989,
  10. Miller, N J, et al. “Antioxidant Activities of Carotenes and Xanthophylls.” FEBS Letters, U.S. National Library of Medicine, 22 Apr. 1996,
  11. “National Library of Medicine – National Institutes of Health.” U.S. National Library of Medicine, National Institutes of Health,
  12. Tadmor, Y., et al. “Comparative Fruit Colouration in Watermelon and Tomato.” Food Research International, Elsevier, 28 June 2005,
  13. “USDA Nutrient Data Laboratory.” NAL,
  14. Edwards, Alison J, et al. “Consumption of Watermelon Juice Increases Plasma Concentrations of Lycopene and Beta-Carotene in Humans.” The Journal of Nutrition, U.S. National Library of Medicine, Apr. 2003,
  15. Rimando, Agnes M, and Penelope M Perkins-Veazie. “Determination of Citrulline in Watermelon Rind.” Journal of Chromatography. A, U.S. National Library of Medicine, 17 June 2005,
  16. Rimando, Agnes M., and Penelope M. Perkins-Veazie. “Determination of Citrulline in Watermelon Rind.” Journal of Chromatography A, Elsevier, 31 May 2005,
  17. Mandel, H, et al. “Elevated Plasma Citrulline and Arginine Due to Consumption of Citrullus Vulgaris (Watermelon).” Journal of Inherited Metabolic Disease, U.S. National Library of Medicine, 2005,
  18. “Fooddata Central Search Results.” FoodData Central,
  19. Center for Food Safety and Applied Nutrition. “Raw Fruits Poster (Text Version / Accessible Version).” U.S. Food and Drug Administration, FDA,

Disclaimer: This article does not provide medical advice.

The information, including but not limited to text, graphics, images, and other material contained in this article, is for informational purposes only. No material within this article is intended to be a substitute for professional medical advice, diagnosis, or treatment.

This story was originally published August 26, 2022, 1:00 PM.

Profile Image of Shannon Ancrum

Shannon Ancrum is a freelance writer specializing in health content. She’s gifted at unraveling complex medical jargon and explaining it to her readers simply and clearly. McClatchy’s newsrooms were not involved in the creation of this content. We may earn a commission if you make a purchase through one of our links.

Profile Image of Daniel Boyer M.D.

Daniel Boyer is a practicing Doctor of medicine with a passion for medical research. He specializes in molecular biology, histology, and pharmacology. McClatchy’s newsrooms were not involved in the creation of this content. We may earn a commission if you make a purchase through one of our links.