Yes my dear.It has a lot of water in it and as a consequence very little calories.I remember reading in a calorie chart issued by a leading pharmaceutical company many years ago that 100 gms of watermelon has just 21 calories.So even if you eat a Kilogram which is enough to make your stomach bloat,you would have taken only 210 calories.Besudes,it is said to be most beneficial for kidneys and helps keep the blood pressure in control.