A personal seedless watermelon typically weighs around 5-8 pounds. The number of calories in a watermelon depends on its weight. On average, 1 cup (about 152 grams) of watermelon contains:
- Calories: 46
- Carbs: 11.5 grams
- Sugar: 9.4 grams
- Fiber: 0.6 grams
So a 5 pound personal seedless watermelon would contain approximately:
- 1160 calories
- 290 grams of carbs
- 235 grams of sugar
- 15 grams of fiber
And an 8 pound personal seedless watermelon would have around:
- 1856 calories
- 464 grams of carbs
- 376 grams of sugar
- 24 grams of fiber
Nutrition Facts of Watermelon
Watermelon is low in calories but high in certain nutrients. Here is the nutrition breakdown for 1 cup (152g) of watermelon (3):
| Nutrient | Amount |
|---|---|
| Calories | 46 |
| Carbs | 11.5 grams |
| Sugar | 9.4 grams |
| Fiber | 0.6 grams |
| Protein | 0.9 grams |
| Vitamin A | 18% DV |
| Vitamin C | 17% DV |
| Potassium | 5% DV |
Watermelon is very low in fat, cholesterol and sodium. It provides some fiber, vitamin A, vitamin C and potassium. But its main nutrients are water and carbohydrates.
Carb Content
The carb content comes mostly from simple sugars, such as glucose, fructose and sucrose. Despite the high sugar content, the glycemic index (GI) of watermelon is only 72, which is considered a low-to-medium GI food (1, 2).
The glycemic index is a measure of how quickly blood sugar rises after eating a food. Lower GI foods provide a slower, more gradual release of sugar into the bloodstream.
However, despite its relatively low GI, watermelon does contain considerable carbs and sugar, so it’s important to keep portion sizes under control.
Water Content
As the name implies, watermelon consists of a lot of water — around 92%, in fact (1).
This means watermelon hydrates you efficiently, especially during hot summer days.
It contains even more water than other hydrating fruits like peaches and oranges, which contain around 88–90% water (4).
Seedless vs Seeded Watermelon
Seedless watermelons are becoming increasingly popular. They have been specially cultivated to lack mature black seeds.
Seedless watermelons are identical to seeded watermelons, apart from the lack of seeds. Although some people prefer seedless watermelons, seeded varieties tend to be sweeter.
Both seeded and seedless varieties contain similar amounts of nutrients. The main difference is that seeded watermelons are more difficult to eat, as you need to spit out the seeds as you chew.
Calories in Watermelon Juice
Watermelon juice made from blended watermelon flesh contains a similar nutrient profile as whole watermelon.
However, the juices available from the supermarket are usually sweetened with extra sugar and can be high in calories.
For example, one cup (240 ml) of Jumex watermelon juice contains 140 calories, which is a much higher calorie count than fresh watermelon juice prepared from the fruit (5).
Whole blended watermelon is more filling and nutritious than watermelon juice. Additionally, the fiber is removed during the juicing process.
How Many Calories in Different Sizes of Watermelon
The number of calories in watermelon depends on the weight of the fruit, which can vary.
Here is an overview of the estimated calories per different sizes of whole, unsweetened watermelon (1):
| Watermelon size | Estimated calories |
|---|---|
| 1 cup, diced (152 grams) | 46 |
| 1 small wedge (1/16 medium melon, 600 g) | 186 |
| 1/8 medium (680 g) | 212 |
| 1/4 medium (1.4 kg) | 432 |
| 1/2 medium (2.7 kg) | 828 |
| 1 medium (5.4 kg) | 1656 |
Keep in mind that if you add any sugar to your watermelon, you will be adding calories. Stay away from presweetened watermelon products if you want to maximize nutrient intake and minimize calories.
Health Benefits of Watermelon
Watermelon is more than just a refreshing, low-calorie summer treat. It provides some impressive health benefits as well.
May Improve Heart Health
Watermelon contains citrulline, an amino acid that may increase nitric oxide levels in the body. Nitric oxide helps your blood vessels expand, which lowers blood pressure (6, 7).
Other studies have observed benefits for heart health. Eating watermelon was linked to lower blood pressure and cholesterol levels in obese adults (8).
Watermelon may also reduce oxidative damage to cholesterol, potentially lowering the risk of heart disease (9).
May Help Prevent Macular Degeneration
Watermelon contains zeaxanthin and lutein, two compounds associated with protection against age-related macular degeneration (AMD) (10).
This disease causes blurriness or loss of vision in the center field of vision due to damage to the retina.
May Help Relieve Muscle Soreness
Watermelon juice appears to reduce muscle soreness and heart rate following exercise in athletes. It seems especially effective when consumed as a blended juice with beetroot (11, 12).
This effect may be due to watermelon’s amino acid citrulline, which is thought to improve exercise performance and recovery time (13).
May Help Prevent Kidney Stones
Watermelon contains citrulline, which is related to lower levels of certain substances that can form kidney stones (14).
Drinking watermelon juice increases levels of citrulline in the blood and urine. Interestingly, studies show that watermelon may have properties that reduce kidney stone formation (15).
May Help Reduce Cancer Risk
Like other fruits and vegetables with potential antioxidant effects, watermelon may help lower your cancer risk. However, study results are mixed.
While some studies link watermelon to reduced risks of cancers of the digestive tract (16), others find no protective effect (17, 18).
More studies are needed to fully understand the anticancer properties of watermelon.
Downsides of Eating Too Much Watermelon
Watermelon is very healthy and safe to consume when eaten in normal food amounts. However, eating too much of any food can cause problems.
May Cause Loose Stools or Diarrhea
Like other water-rich and fiber-rich fruits and vegetables, too much watermelon can easily cause digestive issues.
Eating a large amount of any fruit or vegetable at once may temporarily cause loose stools or diarrhea.
May Be Unsafe for Those With Oral Allergy Syndrome
People who have oral allergy syndrome may experience itchiness, swelling or irritation of the lips, mouth and throat after eating watermelon. This is caused by cross-reactivity between pollen proteins and related food proteins (19).
Contains Lower Nutrient Density Than Other Fruits
Since watermelon is so low in calories, the nutrient density is also lower compared to other fruits.
While watermelon provides some fiber, vitamin C, vitamin A and potassium, it does not supply much protein, vitamin K, thiamine, riboflavin, niacin, vitamin B6, folate, pantothenic acid, iron, zinc, phosphorus, magnesium or selenium (1).
The highest nutrient densities are found in citrus fruits, berries, tropical fruits and tomatoes. These should make up a larger proportion of your fruit intake.
May Contain Pesticide Residues
Watermelons may contain measurable levels of pesticides. They are on the Environmental Working Group’s Dirty Dozen Plus list of the most pesticide-contaminated foods (20).
If you want to minimize your pesticide exposure, always wash, peel and cut watermelons after bringing them home from the store.
The Bottom Line
Watermelon is very low in calories yet high in water and some nutrients. It provides vitamin C, beta-carotene and lycopene. Eating watermelon may benefit heart health, aid recovery after exercise and help prevent some forms of cancer.
Make sure to control portion sizes, since this fruit does contain sugar. At the end of the day, watermelon is a healthy and refreshing addition to your diet.
