Watermelon mostly contains water and some carbohydrates. It contains very low calories, yet provides an exceptional refreshment. Its carbohydrates are mostly composed of simple sugars such as glucose, fructose, and sucrose. 

It is also a good source of Vitamin C that serves as an antioxidant, preventing cell damage, and essential for your immune function, Potassium that is good for your heart and blood pressure, Vitamin B5, and beta carotene that is convertible to Vitamin A. 

With tons of nutrients, Watermelon shows a lot of health benefits such as lowering the blood pressure, reduced insulin resistance, and prevents muscle soreness.