A cup of ice cream will set you back around 300 calories. You can enjoy the same amount of watermelon for just 45.6 calories. And unlike many other desserts, it’s fat-free, cholesterol free, and has no sodium. Plus, the water in it will help you stay fuller longer. To make an easy sorbet, puree some watermelon in your blender, add a squeeze of lime, and pop in the freezer until it hardens.