surprise that watermelon, a thirst-quenching summer favourite, is made up of 91% water. Watermelons are also low in calories and sugar, and a source of Vitamin A, which helps to keep your eyes, skin and immune system in good working order. Ways to enjoy watermelon: Cut a watermelon into triangles and top with berries to make watermelon pizza slices, or make colourful fruit kebabs using different varieties of watermelons.