A kale tonic is a type of green smoothie that is made with kale, water, and a sweetener. The amount of sugar in a kale tonic depends on the type and amount of sweetener used. For example, if you use 1 tablespoon of honey, the kale tonic will have about 4 grams of sugar. However, if you use 1 tablespoon of sugar, the kale tonic will have about 9 grams of sugar.