Is watermelon good for you? How much?
Watermelon is rich in nutrients – including vitamins A and C, B vitamins and potassium — but where it really packs a punch is with lycopene, the antioxidant pigment that gives the fruit its deep red color. Some studies suggest that lycopene may have cardiovascular benefits, including reducing the risk of stroke, and eating watermelon may slightly lower blood pressure. Researchers have also looked at lycopene’s possible role in protecting against various cancers, though evidence is scant.
You can get lycopene from tomatoes, particularly cooked and stewed tomatoes, but “on a fresh basis, you can’t do better than watermelon,” said Penelope Perkins-Veazie, a professor at North Carolina State University in Raleigh who has studied lycopene and is an unpaid science adviser to the National Watermelon Promotion Board. Red watermelon has more lycopene than other watermelon varieties, and “seedless watermelon tends to have more,” she said.
Lycopene from watermelon is also easily absorbed into the body. In one small study, researchers gave volunteers lycopene from tomato juice and lycopene from watermelon; the tomato juice had received heat treatments to boost absorption. They found the two groups had similar blood levels of lycopene.
Though watermelon doesn’t have as much fiber as many other fruits and vegetables, it is fat-free, contains a lot of water and is low in calories, with about 45 calories in a one-cup serving.
Many people worry about the amount of sugar in watermelon, but “that’s a bit of a misconception, because the sugar content is actually lower than some other fruits, gram for gram,” said Jennifer McDaniel, a registered dietitian and spokeswoman for the Academy of Nutrition and Dietetics. While a cup of diced watermelon hasabout nine grams of sugar, a medium banana contains 14 to 15 grams of sugar, as does a cup of blueberries. Dietary guidelines recommend adults eat two cups of fruit a day.
And while watermelon has a high glycemic index, a measure of a food’s ability to raise blood sugar levels, that also adds to the confusion. In fact, its high water content gives it a low glycemic load, meaning it does not raise blood sugar levels quickly in amounts typically eaten.