Watermelon is a popular summer staple and a mainstay of picnics, where its juicy, pink fruit is bitten into by adults and children alike.

The fruit is already known as an excellent way to hydrate and a top alternative to sugary fruit juices or soft drinks.

But now, nutritionists say it could do more than just quench your thirst – adding it is a nutrient ‘powerhouse’ that can boost heart health and even aid weight loss.

A cup of diced watermelon, about 152 grams or nearly one slice, contains 46 calories, 9 grams of sugar and is 91 percent water, making it a healthy sweet treat.

At the same time, its flesh contains more lycopene per serving than any other fruit or vegetable – the antioxidant behind its red color that can slash inflammation and boost heart health.

It also contains a wealth of other nutrients, including the amino acid L-citrulline, which can help to lower blood pressure and cholesterol.

Dr Tiffany Bruno, a nutritionist at Switch4Good, told the Daily Mail: ‘Watermelon is high in the antioxidant lycopene, which benefits cardiovascular health, plus the amino acid citrulline, which improves blood flow and supports healthy blood pressure.

‘It’s also naturally high in potassium and magnesium, enhancing its hydration properties.’

Nutritionists say that watermelon can do much more than just hydrate you (stock image)

She added: ‘While it’s delicious on its own, it can add brightness and sweetness to salads, mocktails, or even grilled and served as a side.’

Nutritionists say the fruit can be eaten on its own in slices, in foods such as salads, or as a juice to get the nutritional benefits.

According to the USDA, alongside its low calorie count, a cup of diced watermelon contains 12 grams of carbohydrates and zero fat or sodium.

It is also a powerhouse for other nutrients. 

This same serving contains about seven to 11 milligrams of lycopene on average. Lycopene is a powerful antioxidant and highly praised by experts for its ability to fight cell damage by reducing the number of free radicals, or molecules that damage structures, in cells.

There are also about 250 to 365 milligrams of L-citrulline in a cup of watermelon. This substance is used by the body to make nitric oxide, which helps blood vessels to relax and better regulate blood pressure.

Additionally, a cup also contains 865 international units of vitamin A, equivalent to someone’s daily requirement and responsible for supporting immune function, 12 milligrams of vitamin C, which also helps to fight inflammation and cellular damage, about 10 percent of daily requirements, and 170 milligrams of potassium, which helps to enable muscle contractions.

Watermelon can help to boost heart health, studies suggest (stock image)

Lara Whitson, a registered nutritionist, told the Cleveland Clinic: ‘We think of watermelon as a fun, seasonal food for barbeques and the beach, but it’s also really good for you. 

‘It’s low in calories, keeps you hydrated and provides many other nutrients that can help you maintain good health.’ 

A meta-analysis of nine studies on lycopene published in 2025 showed people who consumed more of the nutrient had significant improvements in their blood pressure and a lower risk of heart disease. 

The analysis concluded that daily intake of five to 30 milligrams of lycopene, equivalent to one watermelon slice or one or two tomatoes, appeared to be beneficial.

A separate 2022 paper from Louisiana State University investigated whether watermelon juice could protect blood vessel function. 

In the study, 18 healthy young adults consumed watermelon juice for two weeks. 

Results showed that the juice helped to maintain their blood vessel function and their heart rate variability, or fluctuations between heartbeats.

Other studies have also suggested that eating watermelon can help to drive weight loss, including a 2019 study that monitored 33 overweight and obese people. 

For one four-week period, individuals ate watermelon daily and then, for another four weeks, they ate one low-fat cookie every 24 hours.

Participants said they felt less hungry during the watermelon month, while results also show they had slight drops in body weight and blood pressure while consuming the fruit.

A separate 2023 study also highlighted the weight loss benefits. It involved children aged 10 to 17 years who drank a cup of blended watermelon every day for eight weeks and then drank a sugary drink with the same number of calories for the same period.

Results showed that drinking watermelon juice led to mild improvements in body fat and overall weight.