Prevention Magazine's SASSY WATER: A Flat Belly Diet Staple. 2 liters water (about 8 ½ cups) 1 teaspoon freshly grated ginger 1 medium cucumber, peeled and thinly sliced 1 medium lemon, thinly sliced 12 small spearmint leaves. Combine all ingredients in a large pitcher and let flavors blend overnight. Drink the entire pitcher by the end of each day. This just sounds good!