WatermelonFruit

kcal / 100g

kcal / 1 NLEA serving

2 things to watch for

High-ProteinLow-Sugar

Dairy-FreeEgg-FreeGluten-FreeKetoLow-CalorieLow-CarbLow-FatNut-FreePalm Oil FreeSoy-FreeVeganVegetarian

Informational only, not medical advice. Always verify against the physical product label — data may be incomplete or out of date.

Nutrition Facts (per 100g)

Nutrient	Amount	%DV
Energy	30kcal	—
Protein	0.61g	1%
Total lipid (fat)	0.15g	0%
Fatty acids, total saturated	0.016g	0%
Cholesterol	0mg	0%
Carbohydrate, by difference	7.55g	3%
Fiber, total dietary	0.4g	1%
Total Sugars	6.2g	—
Sodium, Na	1mg	0%

Vitamins & Minerals

Calcium, Ca7mg (1% NRV)

Iron, Fe0.24mg (2% NRV)

Potassium, K112mg (6% NRV)

Magnesium, Mg10mg (3% NRV)

Phosphorus, P11mg (2% NRV)

Zinc, Zn0.1mg (1% NRV)

Copper, Cu0.042mg (4% NRV)

Manganese, Mn0.038mg (2% NRV)

Selenium, Se0.4µg (1% NRV)

Vitamin A, RAE28µg (4% NRV)

Vitamin C, total ascorbic acid8.1mg (10% NRV)

Vitamin D (D2 + D3)0µg (0% NRV)

Vitamin E (alpha-tocopherol)0.05mg (0% NRV)

Vitamin K (phylloquinone)0.1µg (0% NRV)

Thiamin0.033mg (3% NRV)

Riboflavin0.021mg (2% NRV)

Niacin0.178mg (1% NRV)

Vitamin B-60.045mg (3% NRV)

Folate, total3µg (2% NRV)

Vitamin B-120µg (0% NRV)

Diet Compatibility

VeganYes
Yes — Watermelon is vegan.
Based on Open Food Facts ingredient analysis. How we set this
VegetarianYes
Yes — Watermelon is vegetarian.
Based on Open Food Facts ingredient analysis. How we set this
Palm Oil FreeYes
Yes — Watermelon is palm oil free.
Based on Open Food Facts ingredient analysis. How we set this
Gluten-FreeYes
Yes — Watermelon is gluten-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
Dairy-FreeYes
Yes — Watermelon is dairy-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
Nut-FreeYes
Yes — Watermelon is nut-free.
Based on the ingredient list and allergen data recorded in Open Food Facts (covers tree nuts and peanuts). How we set this
Soy-FreeYes
Yes — Watermelon is soy-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
Egg-FreeYes
Yes — Watermelon is egg-free.
Based on the ingredient list and allergen data recorded in Open Food Facts. How we set this
KetoYes
Yes — Watermelon is keto-friendly (7.15 g net carbs per 100g, within the ≤10 g net carbs bar). (may not account for sugar alcohols; per-100g basis is a rougher heuristic than per-serving.)
≤5g net carbs per serving — our bar, not a regulatory standard. How we set this
Low-CarbYes
Yes — Watermelon is low-carb (7.15 g net carbs per 100g, within the ≤15 g net carbs bar). (may not account for sugar alcohols.)
≤15g net carbs per serving — our bar, not a regulatory standard. How we set this
Low-SugarNo
No — Watermelon is not low in sugar (6.2 g sugar per 100g, over the ≤5 g sugar bar).
≤5g sugar per serving — our own criterion; the FDA defines none. How we set this
High-ProteinNo
No — Watermelon is not high in protein (0.61 g protein per 100g, below the ≥10 g protein bar).
≥10g protein per serving — FDA 21 CFR 101.54 (≥20% DV). How we set this
Low-FatYes
Yes — Watermelon is low-fat (0.15 g fat per 100g, within the ≤3 g fat bar).
≤3g fat per serving — FDA 21 CFR 101.62. How we set this
Low-CalorieYes
Yes — Watermelon is low-calorie (30 kcal per 100g, within the ≤40 kcal bar).
≤40 kcal per serving — FDA 21 CFR 101.60. How we set this

Read the sourced research

A 1-cup (152g) serving of watermelon has about 11.5g of carbs, low enough to fit a ketogenic diet in moderation, per Healthline.

Because watermelon is relatively high in sugar for its carb count, a full cup can still eat into a meaningful share of a strict 20-50g daily carb budget. ^[7]
Monash University classifies watermelon as high-FODMAP because of its excess fructose content.

Even small servings can trigger symptoms in people with fructose malabsorption or IBS, since watermelon's fructose exceeds its glucose and can overwhelm the gut's fructose transporters. ^[8]
Watermelon's main documented allergen is Cit la 2, a profilin protein that cross-reacts with ragweed pollen and other Cucurbitaceae/profilin foods, per Thermo Fisher's allergen encyclopedia.

Documented cross-reactivity includes cantaloupe, honeydew, cucumber, and zucchini, plus occasional individual case reports involving celery, carrot, tomato, banana, and latex. ^[9]
A study of 1,000 ragweed-pollen-allergic patients found watermelon-induced oral allergy syndrome in about 23% of those with broad pollen sensitization (more than 3 types), versus about 1% with narrower sensitization.

This reaction tracks specifically with people already sensitized to multiple pollens, not the general population. ^[10]

Health Benefits

Watermelon products supplying at least 4g/day of L-citrulline lowered blood pressure over 4-6 weeks in adults with prehypertension, hypertension, or obesity, per a 2022 review of controlled trials.

That dose usually requires concentrated juice or extract, not whole fruit, and lower doses (about 1.6-2.3g/day) mostly showed no effect. ^[1]
A cyclist trial found watermelon juice with just 1.17-1.2g of L-citrulline reduced next-day muscle soreness versus a placebo drink.

It didn't improve performance measures like pedaling cadence, and later reviews describe the soreness benefit as inconsistent across studies. ^[2]
Watermelon has a high glycemic index, roughly 72-80 out of 100, per the Linus Pauling Institute at Oregon State University — comparable to a doughnut.

Glycemic index alone measures how fast a food raises blood sugar, not how much sugar a serving actually delivers. ^[3]
A typical 120g watermelon serving has a much lower glycemic load, around 4-8, according to Harvard Health.

That's because a serving is mostly water with little actual carbohydrate, so the real-world effect on blood sugar stays modest despite the high GI number. ^[4]
A published case report describes an end-stage renal disease patient who developed hyperkalemia — dangerously high blood potassium — after eating excessive amounts of watermelon.

People with significant kidney impairment or on a potassium-restricted diet should keep portions modest and check with their care team. ^[5]

Storage & Buying Tips

Store whole watermelon at 50-60°F (10-15.5°C) for best quality — it'll keep about 10 days below 75°F, or only about 5 days if it's warmer than that.

Don't refrigerate a whole melon at typical fridge temps (32-45°F): that range causes chilling injury — pitting, off-flavors, color loss.

Once cut, handle it like any perishable: refrigerate promptly and toss it if it's sat more than 2 hours between 41-135°F. ^[6]

Frequently Asked Questions

Is it safe to eat watermelon seeds?

Both the white and black seeds are non-toxic, whether you swallow them whole or chew them.

Eating a lot at once can cause mild bloating or gas from their fiber and fat, and whole seeds are a choking hazard for young kids — supervise, or go seedless. ^[11]

Can pregnant women eat watermelon every day?

Watermelon is generally considered safe during pregnancy.

Its high water content helps meet pregnancy's extra fluid needs, which can ease constipation and hemorrhoids — though other water-rich produce does the same thing.

Because watermelon is fairly carb-dense and low in fiber, women with diabetes or gestational diabetes may want to watch portion size.

And as with any cut fruit, don't let it sit out more than about 2 hours before refrigerating. ^[12]

Can you cook or grill watermelon?

Yes — grilling it hot and fast, about 2-4 minutes per side after a light oil brush, chars the surface and caramelizes the sugars while the center stays juicy, similar to a rare steak.

It's typically served warm in savory salads with feta, halloumi, lime, or chili rather than eaten plain. ^[13]

Is watermelon rind safe to pickle and eat?

Yes — pickling watermelon rind is a long Southern US tradition, usually an overnight salt soak to tenderize it followed by a simmer in a vinegar-sugar-spice brine (cinnamon, cloves, and allspice are common).

The rind isn't just a scrap byproduct either: it actually contains more L-citrulline than the pulp (about 60-500mg/100g versus 40-160mg/100g), plus vitamin A, potassium, and phenolic compounds. ^[14]

Why does watermelon make me pee more?

The simplest explanation is watermelon's very high water content (about 91-92%) plus a meaningful potassium load, both of which support urine production.

A rat-model study also found watermelon pulp extract increased urine output and reduced kidney-stone-forming crystals. That's animal evidence, not a human trial, so read it as a plausible mechanism, not settled proof. ^[15]

How can you tell if a whole watermelon is ripe without cutting it?

Weight is a good clue — watermelon is about 91-92% water, so a heavier melon for its size usually means more juice.

Beyond that, look for a dull rind rather than a shiny one, plus a firm, symmetrical shape with no bruises or soft spots. Check the underside 'ground spot' too — creamy yellow-to-buttery-white means ripe, plain white means it was picked too early. ^[6]

Found in these products

None of the products in our database currently contain Watermelon.

Sources & Last Updated

Nutrition data: USDA FoodData Central, “Watermelon, raw” (SR Legacy, fdcId 167765), updated 2026-08-27.

Research reviewed 2026-08-27.