Foodstruct Nutrition Search | Diet Analysis | Food Comparison | Glycemic Index Chart | Insulin Index Chart | Blog | Subscribe

Watermelon nutrition: glycemic index, calories, net carbs, diets

Watermelon, raw
*all the values are displayed for the amount of 100 grams
Article author photo Victoria Mazmanyan by Victoria Mazmanyan | Last updated on December 13, 2021
Education: General Medicine at YSMU


Watermelon has become a symbol of summer in numerous cultures. It is refreshing, bright, and consists of more than ninety percent water, hence the name.

In this article, we will talk about the part of the watermelon that isn’t water, how it affects our health and how it fits in different diets.


In its botanical classification, watermelon is referred to as a pepo: a modified berry with a thick and hard outer rind. It is loosely considered to be a melon; however, it is not in the Cucumis genus of melons. Instead, it is in the same Cucurbitaceae family as melons, cucumbers, and pumpkins.

The stripes of a watermelon indicate its variety. There are over 1200 watermelon varieties; however, the most popular ones are the seeded, seedless, mini, or yellow and orange watermelons.


The origin of watermelon is disputable. Scientists agree that watermelon’s progenitor was cultivated in the continent of Africa. The debate starts with the question of where exactly.

5000-year-old remnants of watermelon seeds were found in Libya. In Egyptian tombs, there were not only 4000-year-old seeds but also paintings of watermelons. Centuries later, it spread and found popularity in Mediterranean countries (1).


Every part of the watermelon is technically edible; thus, it is considered to be a zero-waste food. Naturally, watermelon seeds and the rind have different nutrition values compared to the red flesh. The seeds are often roasted, and the rind can be used as a vegetable, stewed or fried, as well as pickled.

Some recommend incorporating watermelon seeds in traditional recipes, especially in areas where chronic hunger is an issue, as it is usually locally available and thrown away, to improve the intake of protein, fat, calcium, carbohydrate, phosphorus (2).

Macronutrients and Calories

Around 92% of a watermelon’s weight is water, and only the remaining 8% consists of nutrients.

One average serving size of watermelon per person is considered to be one slice or 280g.

A 100g of watermelon contains only 30 calories, while one average serving contains 84.

Macronutrients chart

8% 89%
Daily Value: 1%
0.61 g of 50 g
Daily Value: 0%
0.15 g of 65 g
Daily Value: 3%
7.55 g of 300 g
Daily Value: 5%
91.45 g of 2,000 g
0.24 g


The predominant macronutrients in watermelon are carbohydrates. Of the 8% nutrients of watermelon, 7.55g consists of carbohydrates.

The watermelon pulp is very low in fiber, containing only 0.95g of it. The other 7.15g are composed of net carbs.

One average serving size of watermelon provides 20g of net carbs.

The net carb content contains mainly sugars, such as fructose, glucose, sucrose, and only a small amount of maltose.

Carbohydrate type breakdown

19% 25% 54%
Starch: 0 g
Sucrose: 1.21 g
Glucose: 1.58 g
Fructose: 3.36 g
Lactose: 0 g
Maltose: 0.06 g
Galactose: 0 g

Protein and Fats

The protein concentration is very low, with only 0.6g of it in 100g of watermelon. It also has an insignificant amount of fats; therefore, it is low in saturated fats and has no trans fats or cholesterol.

In protein quality breakdown, out of all the essential amino acids, tryptophan, threonine, and lysine are contained in equal amounts and have the highest concentration. The rest of the essential amino acids are also equal in amounts, but each makes up only 1% of the protein.

Seeds and Rind

Watermelon seeds have a lot more protein (around 8%) and fats (around 17%), as well as fiber (around 40%) and calories; however, it is much more difficult to consume 100g of watermelon seeds (3).

Another study about the nutritional values of watermelon seeds has found very different numbers, putting protein at around 34%, 32% fat, 27% carbohydrates, and 0.1% of dietary fiber (4).

The watermelon rind is rich in a non-essential amino acid called citrulline, which is also found in the flesh. Red flesh watermelon has slightly less citrulline than yellow and orange flesh watermelons (5).


Watermelon is an excellent source of vitamin A and vitamin C. It falls in the top 26% of foods as a source for these vitamins.

It also contains low to moderate amounts of B complex vitamins, particularly B1, B2, B3, B5, and B6. It is low in vitamin K and vitamin E.

Watermelons are completely absent in vitamin D, vitamin B12, and vitamin B9.

Watermelon seeds are rich in vitamin E and vitamin C (4). They are also much higher in vitamin B3 compared to the flesh (6).

The rind of a watermelon is richer in vitamin A and contains high amounts of vitamin C (6).

Vitamin coverage chart

Vitamin A Vitamin E Vitamin D Vitamin C Vitamin B1 Vitamin B2 Vitamin B3 Vitamin B5 Vitamin B6 Folate Vitamin B12 Vitamin K 35% 1% 0% 27% 9% 5% 4% 14% 11% 3% 0% 1%
Vitamin A: 569 IU of 5,000 IU 11%
Vitamin E : 0.05 mg of 15 mg 0%
Vitamin D: 0 µg of 10 µg 0%
Vitamin C: 8.1 mg of 90 mg 9%
Vitamin B1: 0.033 mg of 1 mg 3%
Vitamin B2: 0.021 mg of 1 mg 2%
Vitamin B3: 0.178 mg of 16 mg 1%
Vitamin B5: 0.221 mg of 5 mg 4%
Vitamin B6: 0.045 mg of 1 mg 3%
Folate: 3 µg of 400 µg 1%
Vitamin B12: 0 µg of 2 µg 0%
Vitamin K: 0.1 µg of 120 µg 0%


Watermelon alone is not a great source of minerals. However, watermelon pulp is relatively high in potassium, manganese, magnesium, calcium, and phosphorus.

It has moderate amounts of copper, iron, zinc, selenium, and choline. It is very low in sodium.

Watermelon seeds also contain appreciable minerals; calcium, phosphorus, magnesium, sodium, potassium, and zinc (3).

Mineral coverage chart

Calcium Iron Magnesium Phosphorus Potassium Sodium Zinc Copper Manganese Selenium Choline 3% 9% 8% 5% 10% 1% 3% 14% 5% 3% 3%
Calcium: 7 mg of 1,000 mg 1%
Iron: 0.24 mg of 8 mg 3%
Magnesium: 10 mg of 420 mg 2%
Phosphorus: 11 mg of 700 mg 2%
Potassium: 112 mg of 3,400 mg 3%
Sodium: 1 mg of 2,300 mg 0%
Zinc: 0.1 mg of 11 mg 1%
Copper: 0.042 mg of 1 mg 5%
Manganese: 0.038 mg of 2 mg 2%
Selenium: 0.4 µg of 55 µg 1%
Choline: 4.1 mg of 550 mg 1%

Glycemic Index (GI)

Based on the numbers from The International Tables of Glycemic Index, the glycemic index of a raw watermelon from Australia containing 10g of carbohydrates is 80±3. In parallel with that, a raw watermelon containing 25g of carbohydrates has a GI of 72±13. The difference in carbohydrate concentration is based on the season and the growing environment.

Based on these numbers, the average GI of watermelon is 76 (7).

Despite the high GI, watermelon’s glycemic load of 4-6 is low, meaning one serving of watermelon contains only 6g of carbohydrates.

According to Harvard Health Publishing, a raw watermelon has a GI of 76±4 (8).

Another study has shown different numbers for a GI of a watermelon. They found red-fleshed seedless watermelon to have a GI of 51±2. Red-fleshed seeded watermelon has a slightly lower GI of 48±1, with yellow-fleshed watermelon having an even lower GI of 47±2. This study has shown no difference between the GI of a red-fleshed seedless watermelon and the juice extracted from it. (9)

Other researches have shown that watermelon from the Philippines has a GI of 48±4 and Malaysian watermelon has a GI of 55±3 (10, 11).

A watermelon’s glycemic index can be high or low, depending on the maturity stage, fiber and fat content, processing and treatment of the sample, and other factors.

Despite all these positive effects, people with diabetes are advised to moderate watermelon intake and combine high sugar fruits with healthy fats, fiber, and proteins to slow the absorption of glucose into the bloodstream.

Health Impact


Watermelons have an average glycemic index of 76, but that number can change depending on the maturity and carbohydrate composition of the watermelon.

Watermelons get their bright color from a carotenoid called lycopene. This compound has gained attention from scientists due to its bioavailability and high absorption levels in a watermelon. It has been proven to positively affect the cardiovascular system while also playing a role in defending the organism from diseases such as diabetes and cancer (12).

Another important component of a watermelon is the non-essential amino acid called L-citrulline, which has been studied as a potential non-pharmaceutical treatment for insulin resistance (13). L-citrulline is contained in especially high concentrations in the rind of a watermelon.

Once again, the consumption of watermelon is advised alongside healthy fats, fiber, and protein, such as nuts, for people with diabetic conditions, in order to slow the absorption of glucose.


The amino acid L-citrulline can protect the organism not only from diabetes but can also have a positive therapeutic effect on people with high blood pressure or other cardiovascular diseases (13).

A study has shown that it can effectively reduce the extent of cardiovascular disorders (12).


Watermelon allergies are quite rare but can still occur in both children and adults.

Three major allergens have been described in watermelons; malate dehydrogenase, triosephosphate isomerase, and profilin. Among watermelon allergic patients, the frequencies of sensitization to these compounds are 96, 78, and 56 percent accordingly (14).

These allergens usually cause oral allergy syndrome as the primary manifestation. It commonly presents with immediate swelling and an itching sensation in the mouth after consuming the food allergen (15).

The protein profilin can also be found in other fruits, such as melons and oranges․


As stated previously, the carotenoid lycopene can also potentially have anti-carcinogenic qualities (12).

A group of compounds that the watermelon rind is also rich in is polysaccharides, such as arabinogalactan, galactose, arabinose, rhamnose, and others. These polysaccharides are known for their antiproliferative and antioxidant properties. The antitumor activity of watermelon rind has a significant cytotoxic ability against laryngeal carcinomatous cells (16).

Watermelon rind is also rich in anthocyanin and flavonoids, known for their antioxidant, anti-inflammatory, and anticancer qualities (17).


The antioxidant lycopene has also been proven to have the potential to reduce the development of pre-eclampsia and intrauterine growth retardation in first-time pregnant women (18).

Watermelon can be advised to patients with hyperemesis gravidarum, a pregnancy complication characterized by severe nausea and vomiting, as the high water content can help stay hydrated (19).

Urinary System

Watermelon pulp is known to have protective properties in chronic kidney failure and the potential ability to clear urine. It has been proven to possess significant anti-urolithic and diuretic activities that can help people with bladder or urinary tract issues (20).

Watermelon Diet

As the name suggests, a watermelon diet is a diet during which you only eat watermelon. The high water content in watermelon makes this more of a cleanse than a diet.

Daily consumption of watermelon can lead to a reduction of body weight, body mass index, blood pressure, as well as improve some factors associated with obesity and being overweight. The mechanism for this action is watermelon’s ability to increase perceived satiety and moderate postprandial glucose and insulin response (21).

As a fruit, watermelon has a high density of water with low caloric intake, making it a perfect snack for people trying to lose weight. We’ve already talked about the health benefits of watermelon consumption; however, the watermelon diet is a radical form of dieting. Due to lack of protein and fats, it cannot be recommended to children, pregnant women, and people with conditions such as diabetes or malnourishment.

Watermelon in Diets

Keto The keto diet allows an average of 10-20% of your daily caloric intake to be carbohydrates (22). A 100g of watermelon contains only 8g of carbohydrates; therefore, watermelons can be consumed during a keto diet, with careful management of the carbohydrate intake.
DASH Watermelons are suitable for the DASH diet due to their low sodium and high potassium, magnesium, and fiber concentrations. You can have 4-5 servings of fruits each day (23).
Atkins You can have watermelon if you’re on the third or fourth phases of the Atkins 20 diet or the Atkins 40 diet. However, a cup of watermelon contains 11g of carbohydrates, so you have to eat it in moderation (24).
Mediterranean The Mediterranean diet emphasizes using fruits and vegetables in your eating plan. Watermelon suits this diet perfectly. The Mediterranean watermelon salad is a well-known recipe.
Paleo Even though prehistoric people probably did not eat watermelons, a moderate amount can be acceptable during a paleo diet. It is one of the few sweet fruits that can be used on a paleo diet (25).
Vegan/ Vegetarian/ Pescetarian Since watermelons are plant species, you can naturally eat them on these diets.
Dukan You cannot eat watermelons or fruits in general during the Attack and Cruise phases. You can add watermelon into your diet during the Consolidation phase, but only one serving a day. You can have moderate amounts of watermelon throughout the Stabilization phase (26). Watermelon overall is considered to be a Dukan-friendly food, depending on the phase you’re in (27).
Intermittent Fasting Traditionally you should abstain from watermelon during the fasting period and eat it during the eating periods. However, some believe you can occasionally break the fast with a low-calorie seasonal fruit, like watermelon.
Low Fat & Low Calorie Watermelon has almost no fat and since over 90 percent of it is water, it is one of the best fruits to eat during a low-fat or a low-calorie diet. A 100g serving of watermelon has only 30 calories.
Low Carb Watermelon can be a great option to satisfy your sweet cravings during a low-carb diet, but only in moderation. Keep in mind an average serving of watermelon contains 20g of net carbs.
Anti Inflammatory Watermelon is great for an anti-inflammatory diet due to its properties gained from lycopene, anthocyanin, and flavonoids (12, 17).
BRAT If you are following the BRAT diet for a limited amount of time, you can add watermelon as bland food since it is an excellent source of hydration. However, you have to moderate your intake as large amounts of lycopene consumption can cause diarrhea (28).


  1. The 5,000-Year Secret History of the Watermelon
  8. Glycemic index for 60+ foods
Article author photo Victoria Mazmanyan
Education: General Medicine at YSMU
Last updated: December 13, 2021

Important nutritional characteristics for Watermelon

Glycemic index ⓘ Source:
Check out our Glycemic index chart page for the full list.
76 (high)
Glycemic load
15 (medium)
Insulin index ⓘ Falls in a large range
Net Carbs ⓘ Net Carbs = Total Carbohydrates – Fiber – Sugar Alcohols
7.15 grams
Serving Size ⓘ Serving sizes are taken from FDA's Reference Amounts Customarily Consumed (RACCs)
1 NLEA serving (280 grams)
Acidity (Based on PRAL) ⓘ PRAL (Potential renal acid load) is calculated using a formula. On the PRAL scale the higher the positive value, the more is the acidifying effect on the body. The lower the negative value, the higher the alkalinity of the food. 0 is neutral.
-2 (alkaline)
77% Vitamin A
74% Vitamin C
62% Cryptoxanthin, beta
62% Lycopene
60% Vitamin A RAE
Explanation: The given food contains more Vitamin A than 77% of foods. Note that this food itself is richer in Vitamin A than it is in any other nutrient. Similarly, it is relatively rich in Vitamin C, Cryptoxanthin, beta, Lycopene, and Vitamin A RAE.

Watermelon Glycemic index (GI)

Check out our Glycemic index chart page for the full list.

Watermelon Glycemic load (GL)


Mineral chart - relative view

0.038 mg
TOP 69%
112 mg
TOP 80%
0.042 mg
TOP 84%
10 mg
TOP 84%
7 mg
TOP 85%
0.24 mg
TOP 87%
0.1 mg
TOP 91%
0.4 µg
TOP 91%
11 mg
TOP 92%
4.1 mg
TOP 93%
1 mg
TOP 98%

Vitamin chart - relative view

Vitamin A
569 IU
TOP 23%
Vitamin C
8.1 mg
TOP 26%
Vitamin B5
0.221 mg
TOP 79%
Vitamin B1
0.033 mg
TOP 80%
Vitamin B6
0.045 mg
TOP 80%
3 µg
TOP 87%
Vitamin K
0.1 µg
TOP 88%
Vitamin B3
0.178 mg
TOP 88%
Vitamin B2
0.021 mg
TOP 90%
Vitamin E
0.05 mg
TOP 91%
Vitamin D
0 µg
TOP 100%
Vitamin B12
0 µg
TOP 100%

Protein quality breakdown

Tryptophan Threonine Isoleucine Leucine Lysine Methionine Phenylalanine Valine Histidine 8% 8% 5% 2% 9% 2% 3% 3% 3%
Tryptophan: 7 mg of 280 mg 3%
Threonine: 27 mg of 1,050 mg 3%
Isoleucine: 19 mg of 1,400 mg 1%
Leucine: 18 mg of 2,730 mg 1%
Lysine: 62 mg of 2,100 mg 3%
Methionine: 6 mg of 1,050 mg 1%
Phenylalanine: 15 mg of 1,750 mg 1%
Valine: 16 mg of 1,820 mg 1%
Histidine: 6 mg of 700 mg 1%

Fat type information

16% 36% 49%
Saturated Fat: 0.016 g
Monounsaturated Fat: 0.037 g
Polyunsaturated fat: 0.05 g

Fiber content ratio for Watermelon

82% 5% 13%
Sugar: 6.2 g
Fiber: 0.4 g
Other: 0.95 g

All nutrients for Watermelon per 100g

Nutrient Value DV% In TOP % of foods Comparison
Calories 30kcal 2% 94% 1.6 times less than OrangeOrange
Protein 0.61g 1% 89% 4.6 times less than BroccoliBroccoli
Fats 0.15g 0% 90% 222.1 times less than CheeseCheese
Vitamin C 8.1mg 9% 26% 6.5 times less than LemonLemon
Net carbs 7.15g N/A 52% 7.6 times less than ChocolateChocolate
Carbs 7.55g 3% 54% 3.7 times less than RiceRice
Cholesterol 0mg 0% 100% N/AEgg
Vitamin D 0µg 0% 100% N/AEgg
Iron 0.24mg 3% 87% 10.8 times less than BeefBeef
Calcium 7mg 1% 85% 17.9 times less than MilkMilk
Potassium 112mg 3% 80% 1.3 times less than CucumberCucumber
Magnesium 10mg 2% 84% 14 times less than AlmondAlmond
Sugar 6.2g N/A 46% 1.4 times less than Coca-ColaCoca-Cola
Fiber 0.4g 2% 57% 6 times less than OrangeOrange
Copper 0.04mg 5% 84% 3.4 times less than ShiitakeShiitake
Zinc 0.1mg 1% 91% 63.1 times less than BeefBeef
Starch 0g 0% 100% N/APotato
Phosphorus 11mg 2% 92% 16.5 times less than Chicken meatChicken meat
Sodium 1mg 0% 98% 490 times less than White BreadWhite Bread
Vitamin A 569IU 11% 23% 29.4 times less than CarrotCarrot
Vitamin A RAE 28µg 3% 40%
Vitamin E 0.05mg 0% 91% 29.2 times less than KiwifruitKiwifruit
Manganese 0.04mg 2% 69%
Selenium 0.4µg 1% 91%
Vitamin B1 0.03mg 3% 80% 8.1 times less than Pea rawPea raw
Vitamin B2 0.02mg 2% 90% 6.2 times less than AvocadoAvocado
Vitamin B3 0.18mg 1% 88% 53.8 times less than Turkey meatTurkey meat
Vitamin B5 0.22mg 4% 79% 5.1 times less than Sunflower seedSunflower seed
Vitamin B6 0.05mg 3% 80% 2.6 times less than OatOat
Vitamin B12 0µg 0% 100% N/APork
Vitamin K 0.1µg 0% 88% 1016 times less than BroccoliBroccoli
Folate 3µg 1% 87% 20.3 times less than Brussels sproutBrussels sprout
Trans Fat 0g N/A 100% N/AMargarine
Saturated Fat 0.02g 0% 92% 368.4 times less than BeefBeef
Monounsaturated Fat 0.04g N/A 86% 264.8 times less than AvocadoAvocado
Polyunsaturated fat 0.05g N/A 90% 943.5 times less than WalnutWalnut
Tryptophan 0.01mg 0% 97% 43.6 times less than Chicken meatChicken meat
Threonine 0.03mg 0% 96% 26.7 times less than BeefBeef
Isoleucine 0.02mg 0% 97% 48.1 times less than SalmonSalmon
Leucine 0.02mg 0% 98% 135.1 times less than TunaTuna
Lysine 0.06mg 0% 94% 7.3 times less than TofuTofu
Methionine 0.01mg 0% 97% 16 times less than QuinoaQuinoa
Phenylalanine 0.02mg 0% 97% 44.5 times less than EggEgg
Valine 0.02mg 0% 98% 126.8 times less than Soybean rawSoybean raw
Histidine 0.01mg 0% 98% 124.8 times less than Turkey meatTurkey meat
Fructose 3.36g 4% 82% 1.8 times less than AppleApple
Omega-3 - EPA 0g N/A 100% N/ASalmon
Omega-3 - DHA 0g N/A 100% N/ASalmon
Omega-3 - DPA 0g N/A 100% N/ASalmon

Check out similar food or compare with current


Nutrition Facts
___servings per container
Serving Size ______________
Amount Per 100g
Calories 30
% Daily Value*
Total Fat 0g
Saturated Fat 0g
Trans Fat g
Cholesterol 0mg
Sodium 1mg
Total Carbohydrate 8g
Dietary Fiber 0g
Total Sugars g
Includes ? g Added Sugars
Protein 1g
Vitamin D 0mcg 0%

Calcium 7mg 1%

Iron 0mg 0%

Potassium 112mg 3%

The % Daily Value (DV) tells you how much a nutrient in a serving of food contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.

Health checks

Low in Cholesterol
 ⓘ Dietary cholesterol is not associated with an increased risk of coronary heart disease in healthy individuals. However, dietary cholesterol is common in foods that are high in harmful saturated fats.
No Trans Fats
 ⓘ Trans fat consumption increases the risk of cardiovascular disease and mortality by negatively affecting blood lipid levels.
Low in Saturated Fats
 ⓘ Saturated fat intake can raise total cholesterol and LDL (low-density lipoprotein) levels, leading to an increased risk of atherosclerosis. Dietary guidelines recommend limiting saturated fats to under 10% of calories a day.
Low in Sodium
 ⓘ Increased sodium consumption leads to elevated blood pressure.
Low in Sugars
 ⓘ While the consumption of moderate amounts of added sugars is not detrimental to health, an excessive intake can increase the risk of obesity, and therefore, diabetes.

Watermelon nutrition infographic

Watermelon nutrition infographic
Infographic link


The source of all the nutrient values on the page (excluding the main article and glycemic index text the sources for which are presented separately if present) is the USDA's FoodCentral. The exact link to the food presented on this page can be found below.


Data provided by should be considered and used as information only. Please consult your physician before beginning any diet.