Watermelon is a healthy, hydrating fruit: it’s about 91% water, with only 30 calories per 100 g, and it’s one of the richest common sources of lycopene, the red pigment also found in tomatoes, according to USDA FoodData Central. A cup of diced watermelon (152 g) has about 46 calories and 9 g of natural sugar. It also provides some vitamin C and potassium. Because it’s so watery, it’s filling for very few calories, and one 5 cm slice counts as one of your 5 A Day, according to the NHS.
Watermelon nutrition
Calculated from USDA FoodData Central values for raw watermelon:
| Nutrient | 1 cup diced (152 g) | 1 wedge (286 g) |
|---|---|---|
| Calories | 46 kcal | 86 kcal |
| Carbohydrate | 11.5 g | 21.6 g |
| Sugars | 9.4 g | 17.7 g |
| Fiber | 0.6 g | 1.1 g |
| Vitamin C | 12 mg | 23 mg |
| Potassium | 170 mg | 320 mg |
| Lycopene | 6,900 mcg | 13,000 mcg |
| Water | about 139 g | about 261 g |
A wedge is about a sixteenth of a large watermelon.
Health benefits of watermelon
Hydration
Watermelon is more than 90% water, so it helps a little with your daily fluid intake. EFSA estimates that food supplies about 20% to 30% of the water we take in. Chilled watermelon is especially refreshing in hot weather. Our guide to staying hydrated in hot weather lists other water-rich foods.
Lycopene
Lycopene is the carotenoid that gives watermelon and tomatoes their red color. Per 100 g, raw watermelon contains about 4,500 mcg, according to USDA data. Lycopene acts as an antioxidant in the laboratory. How much it does on its own in the body is less clear, so it’s best to think of watermelon as one part of eating more fruit and vegetables in general.
Eating watermelon with a little fat, such as in a salad with feta and olive oil, may help your body absorb carotenoids. In a small 2004 study, people absorbed far more lycopene and other carotenoids from vegetables eaten with a full-fat dressing than with a fat-free one.
Low in calories, big portion
Watermelon is one of the lowest-calorie fruits. A big bowl is satisfying for under 100 calories, which makes it a good swap for ice cream or sweets on a hot day.
Watermelon and blood sugar
Watermelon contains natural sugar and very little fiber, so it raises blood sugar fairly quickly. But because it’s mostly water, a normal portion contains a moderate amount of carbohydrate: about 11.5 g in a cup. If you have diabetes, keep to a portion, and eat it with a meal or with some protein, such as yogurt or nuts. Our guide to the glycemic index explains why portion size matters as much as the type of food. On strict keto, watermelon is limited to a small slice. Our guide to low-carb fruits compares it with berries.
Food safety with melons
Melons grow on the ground, and bacteria such as Listeria and Salmonella can sit on the rind. When you cut through it, the knife can carry them into the flesh. The FDA advises:
- Scrub the rind with a clean produce brush under running water before cutting.
- Refrigerate cut watermelon and pre-cut melon from the shop.
- Choose pre-cut melon only if it’s refrigerated or kept on ice in the store.
Keep cut watermelon covered in the fridge and eat it within a few days. Don’t leave cut melon out in the sun at a picnic for hours.
How to choose a ripe watermelon
- Heavy for its size: a ripe watermelon is full of water.
- A creamy yellow field spot: the patch where it rested on the ground should be yellow rather than white or pale green.
- A deep, hollow sound when you tap it.
- Firm, unblemished skin without soft spots or cracks.
Whole watermelons keep at room temperature for about a week, or longer in the fridge.
Watermelon compared with other fruit
Per 100 g, from USDA FoodData Central values:
| Fruit (100 g) | Calories | Sugars | Fiber | Vitamin C |
|---|---|---|---|---|
| Watermelon | 30 kcal | 6.2 g | 0.4 g | 8.1 mg |
| Cantaloupe melon | 34 kcal | 7.9 g | 0.9 g | 36.7 mg |
| Strawberries | 32 kcal | 4.9 g | 2.0 g | 58.8 mg |
| Mango | 60 kcal | 13.7 g | 1.6 g | 36.4 mg |
| Banana | 89 kcal | 12.2 g | 2.6 g | 8.7 mg |
Watermelon is one of the lowest-calorie fruits, but cantaloupe and strawberries provide much more vitamin C for similar calories. Eating a mix of fruit gives you the widest range of nutrients.
Can you eat the seeds and rind?
Yes. Watermelon seeds are edible, and many people swallow them without noticing. Roasted seeds make a crunchy snack. The white rind is also edible and is pickled or stir-fried in some cuisines.
Ways to eat watermelon
- On its own, chilled, in wedges or cubes.
- Salad: our strawberry arugula salad works well with watermelon instead of strawberries, or try watermelon with feta, mint and arugula.
- Frozen: cubes frozen on a tray make a cold snack, or blend them into a slushie with lime.
- Water: add a few cubes and mint to a jug of water.
- Salsa: diced watermelon, cucumber, red onion, chili and lime with grilled fish.
- Fruit salad with berries and kiwi.
Common questions
Is watermelon good for weight loss?
It can be a helpful swap, because it’s filling and low in calories. No single food causes weight loss on its own.
Can you eat too much watermelon?
Very large amounts can upset some people’s stomachs, because it contains a natural sugar called fructose. For most people, a few cups a day is fine.
Is watermelon juice as healthy as the fruit?
The fruit is better. Juicing removes the little fiber watermelon has and makes it easy to drink a lot of sugar. The NHS suggests no more than 150 ml of juice and smoothies a day.
Is watermelon good for children?
Yes. It’s a refreshing, hydrating fruit for children. For young children, remove the seeds and cut it into small pieces or strips, and supervise them while they eat.
This article is general information, not medical advice. Talk to your doctor or a registered dietitian before making big changes to how you eat, especially if you have a health condition, take regular medication, or are pregnant or breastfeeding.
