There are several sugar substitutes that work when making homemade lemonade: 1. Stevia: Substituting stevia works but instead of a cup, you will need a teaspoon! Since Stevia is 200-300x sweeter than sugar, it doesn't take much in this lemonade recipe. 2. Coconut Sugar: To replace the sugar with coconut sugar, you will need the same amount, but it takes a little longer to dissolve in water due to the coarse nature of the coconut sugar. 3. Monk Fruit: You can use powdered monk fruit instead of sugar which is sweeter than sugar so you don't need as much. For every 1 cup of sugar the recipe calls for, substitute a 1/3rd cup of powdered monk fruit.