Foodstruct
Advanced Nutrition Search | Diet Analysis

Watermelon nutrition: glycemic index, calories weight loss and diets

Watermelon, raw
*all the values are displayed for the amount of 100 grams

Complete nutrition and health benefits analysis for Watermelon

Watermelon

Watermelon

Introduction

Watermelon has become a symbol of summer in our culture. 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 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. It is in the same Cucurbitaceae family as melons, cucumbers and pumpkins.

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

The origin of watermelons 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).

Nutrition

In the Watermelon nutrition infographic below we tried to visualize some important values

Watermelon nutrition infographic

Watermelon nutrition infographic
Copy infographic link

Every part of a watermelon can be eaten, thus it is considered to be a zero waste food. Watermelon seeds and rind, naturally, have different nutrition values compared to that on the inside. The seeds are often roasted and the rind can be used as a vegetable, stewed or fried, as well as pickled.

Some recommend incorporation of 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 percent of a watermelon’s weight is water. The predominant macronutrients in a watermelon are carbohydrates. The protein concentration is very low, with only 0.6g of it in a 100g of a watermelon. It also has an insignificant amount of fats, therefore it is low in saturated fats and has no trans fats or cholesterol. A 100g of a watermelon contains only 30 calories.

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 make up only 1% of the protein.

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 value of watermelon seeds has found different numbers, with protein at around 34 percent, 32% fat, 27% carbohydrates and 0.1% of dietary fiber (4).

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

Vitamins

Watermelons are a great source of vitamin A and vitamin C. It also contains low to moderate amounts of B complex vitamins, in particular vitamins B1, B2, B3, B5 and B6. It is low in vitamin K and vitamin E. Watermelons are completely absent of vitamin D, vitamin B12 and vitamin B9.

Watermelon seeds are rich in vitamin E (4) and vitamin C. 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).

Minerals

Watermelon pulp is rich 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).

Glycemic Index

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 season and the growing environment. Based on these numbers, the average GI of a watermelon is 76.

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

According to Harvard Health Publishing a raw watermelon has a GI of 76±4.

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 that there is no difference between the GI of a red fleshed seedless watermelon and the juice extracted from it. (3)

Other researches have shown watermelon from the Philippines to have a GI of 48±4 (4) and Malaysian watermelon to have a GI of 55±3 (5).

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

Watermelon consists of over ninety percent water, but another one of watermelon’s components is a carotenoid called lycopene. This is the compound that gives a watermelon its colour and it has gained attention from scientists due to its bioavailability and high absorption levels in a watermelon. It has been studied to have positive effects on cardiovasculature. It has a therapeutic role against life threatening metabolic diseases, such as cancer and diabetes(6).

Another compound found in high concentrations in a watermelon is an amino acid called L-citrulline. It has been proven to benefit cardiovascular health in direct and indirect pathways and can possibly be used as a non-pharmaceutical treatment for insulin resistance, high blood pressure and other cardiovascular diseases (7).

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

Allergy

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

There are three major allergens that have been described in watermelons; malate dehydrogenase, triose phosphate isomerase and profilin. Among watermelon allergic patients, the frequencies of sensitization to these compounds are 96, 78 and 56 percent accordingly (7).

These allergens usually cause oral allergy syndrome as the main manifestation. It commonly presents with immediate swelling and an itching sensation in the mouth after consumption of the food allergen (8).

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

Diabetes

Watermelons have an average glycemic index of 76 (9), 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. It has been proven to have a positive effect on the cardiovascular system, also playing a role in defending the organism from diseases such as diabetes and cancer (10).

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 (11). L-citrulline is contained in especially high concentrations in the rind of a watermelon. 

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

Cancer

As stated previously the carotenoid lycopene can also potentially have anti-carcinogenic qualities (10). 

A group of compounds that the watermelon rind is also rich in are 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 carcinomatose cells (12). 

Watermelon rind is also rich in anthocyanin and flavonoids, which are known for their antioxidant, anti-inflammatory and anticancer qualities (13).

Cardiovascular

The amino acid L-citrulline can protect the organism not only from diabetes but it can also have a positive therapeutic effect on people with high blood pressure or other cardiovascular diseases (11).

A study has shown that it can prove to be effective in reducing the extent of cardiovascular disorders (10).

Pregnancy

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 (14).

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 to stay hydrated (15).

Urinary System

Watermelon pulp is known to have protective properties in chronic kidney failure and a potential ability to clear urine. It has been proven to possess significant anti-urolithiatic and diuretic activities (16) that can help people with bladder or urinary tract issues.

Watermelon Diet

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

Daily consumption of watermelon can lead to 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 (17).

As a fruit, watermelon has a high density of water, with low caloric intake, which makes 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 and due to lack of protein and fats cannot be recommended to children, pregnant women and to people with, such as diabetes or compromised immune functions (18).

Watermelon in Diets

Keto

The keto diet allows an average 10-20% of your daily caloric intake to be carbohydrates (19). A 100g of a watermelon contains only 8g of carbohydrates, therefore watermelons can be consumed during a keto diet, with careful management of the carbohydrate intake (20).

DASH

Watermelons are suitable for both DASH diets due to their low sodium and high potassium, magnesium and fiber concentrations. You can have 4-5 servings of fruits each day (21).

Atkins

You can have watermelon if you’re on the Atkins 20 diet, phases 3 or 4, or on the Atkins 40 diet. However a cup of watermelons contains 11g of carbohydrates, so you have to eat it in moderation (22).

Mediterranean

The Mediterraeian diet emphasizes using fruits and vegetables in your eating plan. Watermelon suits perfectly in this diet. The Mediterranean watermelon salad is a well known recipe.

Paleo

Even though cavemen most probably didn’t eat watermelons, a moderate amount of it is acceptable during a paleo diet, it is one of the few sweet fruits that is (23).

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 (24). Watermelon overall is considered to be a Dukan-friendly food, depending on the phase you’re in (25).

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 seasonal fruit, like watermelon (26).

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 a watermelon has only 30 calories.

Low Carb

Watermelon is a great option to satisfy your sweet cravings during a low carb diet.

Anti Inflammatory

Watermelon is great for an anti-inflammatory diet due to its properties gained from lycopene, anthocyanin and flavonoids (10), (13).

BRAT

If you are following the BRAT diet for a limited amount of time you can add watermelon as a bland food, since it is a great source of hydration. However you have to moderate your intake as large amounts of lycopene consumption can cause diarrhea (27).

Sources.

  1. https://www.nationalgeographic.com/news/2015/08/150821-watermelon-fruit-history-agriculture/
  2. https://pdfs.semanticscholar.org/461c/4889b0ab6f8a34856e50aeac0a3f74d77af7.pdf
  3. https://www.researchgate.net/publication/323663320
  4. http://www.phytojournal.com/archives/2015/vol3issue6/PartB/3-6-24.1.pdf
  5. https://www.researchgate.net/publication/7736564_Determination_of_citrulline_in_watermelon_rind
  6. https://www.researchgate.net/publication/259176510
  7. https://pubmed.ncbi.nlm.nih.gov/19295232/
  8. https://www.researchgate.net/publication/289039646_Oral_allergy_syndrome_to_watermelon_and_melon
  9. https://care.diabetesjournals.org/content/diacare/suppl/2008/09/18/dc08-1239.DC1/TableA1_1.pdf
  10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4464475/
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073798/
  12. https://www.researchgate.net/publication/333828166
  13. https://www.scientific.net/MSF.998.261
  14. https://pubmed.ncbi.nlm.nih.gov/12767566/
  15. https://www.hyperemesis.ie/documents/eating_and_drinking_tips.pdf
  16. https://pubmed.ncbi.nlm.nih.gov/29145146/
  17. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6470521/
  18. https://www.healthline.com/health/diet-weight-loss/watermelon-diet-fact-or-fiction#risks-of-the-diet
  19. https://www.hsph.harvard.edu/nutritionsource/healthy-weight/diet-reviews/ketogenic-diet/
  20. https://www.healthline.com/nutrition/watermelon-keto#carb-content
  21. https://hypertensioninstitute.com/service/dash-1-2-diet/
  22. https://www.atkins.com/how-it-works/library/articles/national-watermelon-day
  23. https://paleogrubs.com/healthiest-paleo-diet-foods
  24. https://www.healthline.com/nutrition/dukan-diet-101#foods
  25. https://www.dukandiet.com/newsletter/june-2013
  26. https://www.ndtv.com/health/intermittent-fasting-break-your-fast-with-these-5-weight-loss-friendly-foods-2103541
  27. https://www.cancer.gov/about-cancer/treatment/cam/patient/prostate-supplements-pdq
  28. https://care.diabetesjournals.org/content/diacare/suppl/2008/09/18/dc08-1239.DC1/TableA1_1.pdf
  29. https://www.health.harvard.edu/diseases-and-conditions/glycemic-index-and-glycemic-load-for-100-foods
  30. http://www.ifrj.upm.edu.my/25%20(06)%202018/(41).pdf
  31. https://www.academia.edu/17584643/
  32. https://www.researchgate.net/publication/5488788
  33. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4464475/
  34. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6073798/

Important nutritional characteristics for Watermelon

Watermelon
Glycemic index ⓘ Gi values are taken from various sources including USDA and NHS. GI values less than 55 are considered as low. Values above 70 are considered as high.
72 (high)
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 PRAL scale the higher the positive value, the more is the acidifying effect on the body. The lower negative value is the more alkaline the effect is. 0 is neutral.
-2 (alkaline)
Calories
30
77% Vitamin A
74% Vitamin C
62% Cryptoxanthin, beta
62% Lycopene
60% Vitamin A, RAE
Explanation: This food contains more Vitamin A than 77% of foods. More importantly, although there are several foods (23%) which contain more Vitamin A, this food itself is rich in Vitamin A more 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)

72
Similar food data
70 Melon Melon
59 Pineapple Pineapple
40 Avocado Avocado

Check out similar food or compare with current

Macronutrients chart

Protein:
Daily Value: 1%
0.61 g of 50 g
1%
Fats:
Daily Value: 0%
0.15 g of 65 g
0%
Carbs:
Daily Value: 3%
7.55 g of 300 g
3%
Water:
Daily Value: 5%
91.45 g of 2,000 g
5%
Other:
0.24 g

NEW NUTRITION FACTS LABEL

Nutrition Facts
___ servings per container
Serving Size ______________
Amount Per Serving
Calories 30
% Daily Value*
0%
Total Fat 0g
0%
Saturated Fat 0g
Trans Fat g
0%
Cholesterol 0mg
0%
Sodium 1mg
3%
TotalCarbohydrate 8g
0%
Dietary Fiber 0g
Total Sugars 6g
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
ok
details
High level of Cholesterol may be dangerous for your health, especially if you suffer from cardio-vascular deseases.
No Trans Fats
ok
details
Trans fats tend to increase risk of coronary heart disease according to various studies. The National Academy of Sciences (NAS) states that trans fats increase levels of LDL and decrease levels of HDL. According to NAS trans fatty acid consumption should be as low as possible while consuming a nutritionally adequate diet.
Low in Saturated Fats
ok
details
Dietary Guidelines for Americans 2015-2020 recommends using less than 10 percent of calories from saturated fats link
Low in Sodium
ok
details
Extensive usage of sodium is not recommended for the people suffering from hypertonia.
Low in Sugars
ok
details
Using too much sugars can lead to weight gain or diabetes.

Mineral coverage chart

Calcium: 7 mg of 1,000 mg 1%
Iron: 0.24 mg of 18 mg 1%
Magnesium: 10 mg of 400 mg 3%
Phosphorus: 11 mg of 1,000 mg 1%
Potassium: 112 mg of 3,500 mg 3%
Sodium: 1 mg of 2,400 mg 0%
Zinc: 0.1 mg of 15 mg 1%
Copper: 0.042 mg of 2 mg 2%
Manganese: 0.038 mg of 2 mg 2%
Selenium: 0.4 µg of 70 µg 1%
Choline: 4.1 mg of 550 mg 1%

Mineral chart - relative view

Manganese
0.038 mg
TOP 69%
Potassium
112 mg
TOP 80%
Copper
0.042 mg
TOP 84%
Magnesium
10 mg
TOP 84%
Calcium
7 mg
TOP 85%
Iron
0.24 mg
TOP 87%
Zinc
0.1 mg
TOP 91%
Selenium
0.4 mg
TOP 91%
Phosphorus
11 mg
TOP 92%
Choline
4.1 mg
TOP 93%
Sodium
1 mg
TOP 98%

Vitamin coverage chart

Vitamin A: 569 IU of 5,000 IU 11%
Vitamin E : 0.05 mg of 20 mg 0%
Vitamin D: 0 µg of 10 µg 0%
Vitamin C: 8.1 mg of 60 mg 14%
Vitamin B1: 0.033 mg of 2 mg 2%
Vitamin B2: 0.021 mg of 2 mg 1%
Vitamin B3: 0.178 mg of 20 mg 1%
Vitamin B5: 0.221 mg of 10 mg 2%
Vitamin B6: 0.045 mg of 2 mg 2%
Folate, total: 3 µg of 400 µg 1%
Vitamin B12: 0 µg of 6 µg 0%
Vitamin K: 0.1 µg of 80 µg 0%
Folic acid (B9): 0 µg of 400 µg 0%

Vitamin chart - relative view

Vitamin A
569 µg
TOP 23%
Vitamin C
8.1 µg
TOP 26%
Vitamin B5
0.221 µg
TOP 79%
Vitamin B1
0.033 µg
TOP 80%
Vitamin B6
0.045 µg
TOP 80%
Folate, total
3 µg
TOP 87%
Vitamin K
0.1 µg
TOP 88%
Vitamin B3
0.178 µg
TOP 88%
Vitamin B2
0.021 µg
TOP 90%
Vitamin E
0.05 µg
TOP 91%
Vitamin D
0 µg
TOP 100%
Vitamin B12
0 µg
TOP 100%
Folic acid (B9)
0 µg
TOP 100%

Protein quality breakdown

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

Saturated Fat: 0.016 g
Monounsaturated Fat: 0.037 g
Polyunsaturated fat: 0.05 g

Carbohyrates breakdown for Watermelon

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

Fiber content / ratio for Watermelon

Sugars: 6.2 g
Fiber: 0.4 g

All nutrients for Watermelon per 100g

Nutrient DV% In TOP % of foods Value Comparison
Protein 1% 89% 0.61g 4.6 times less than Broccoli
Fats 0% 90% 0.15g 222.1 times less than Cheese
Carbs 3% 54% 7.55g 3.7 times less than Rice
Calories 1% 94% 30kcal 1.6 times less than Orange
Starch 0% 100% 0g N/A
Fructose 4% 82% 3.36g 1.8 times less than Apple
Sugars 7% 46% 6.2g 1.4 times less than Coca-Cola
Fiber 1% 57% 0.4g 6 times less than Orange
Calcium 1% 85% 7mg 17.9 times less than Milk
Iron 1% 87% 0.24mg 10.8 times less than Beef
Magnesium 3% 84% 10mg 14 times less than Kidney bean
Phosphorus 2% 92% 11mg 16.5 times less than Chicken meat
Potassium 2% 80% 112mg 1.3 times less than Cucumber
Sodium 0% 98% 1mg 490 times less than White Bread
Zinc 1% 91% 0.1mg 63.1 times less than Beef
Copper 0% 84% 0.04mg 3.4 times less than Shiitake
Vitamin A 11% 23% 569IU 29.4 times less than Carrot
Vitamin E 0% 91% 0.05mg 29.2 times less than Kiwifruit
Vitamin D 0% 100% 0µg N/A
Vitamin C 9% 26% 8.1mg 6.5 times less than Lemon
Vitamin B1 2% 80% 0.03mg 8.1 times less than Pea
Vitamin B2 1% 90% 0.02mg 6.2 times less than Avocado
Vitamin B3 1% 88% 0.18mg 53.8 times less than Turkey meat
Vitamin B5 2% 79% 0.22mg 5.1 times less than Sunflower seed
Vitamin B6 2% 80% 0.05mg 2.6 times less than Oat
Folate, total 1% 87% 3µg 20.3 times less than Brussels sprout
Vitamin B12 0% 100% 0µg N/A
Vitamin K 0% 88% 0.1µg 1016 times less than Broccoli
Folic acid (B9) 0% 100% 0µg N/A
Tryptophan 0% 97% 0.01mg 43.6 times less than Chicken meat
Threonine 0% 96% 0.03mg 26.7 times less than Beef
Isoleucine 0% 97% 0.02mg 48.1 times less than Salmon
Leucine 0% 98% 0.02mg 135.1 times less than Tuna
Lysine 0% 94% 0.06mg 7.3 times less than Tofu
Methionine 0% 97% 0.01mg 16 times less than Quinoa, cooked
Phenylalanine 0% 98% 0.02mg 44.5 times less than Egg
Valine 0% 98% 0.02mg 126.8 times less than Soybean
Histidine 0% 98% 0.01mg 124.8 times less than Turkey meat
Cholesterol 0% 100% 0mg N/A
Trans Fat 0% 100% 0g N/A
Saturated Fat 0% 92% 0.02g 368.4 times less than Beef
Monounsaturated Fat 0% 86% 0.04g 264.8 times less than Avocado
Polyunsaturated fat 0% 90% 0.05g 943.5 times less than Walnut

The main source of information is USDA Food Composition Database (U.S. Department of Agriculture)
Dietary Guidelines for Americans is used as the primary source for advice in this web resource
Data provided by FoodStruct.com should be considered and used as information only. Please consult your physician before beginning any diet.