Stevia: This sweetener, which looks a lot like its white sugar counterpart, comes from the leaves of a stevia plant. The herb contains zero calories and does not raise blood sugar levels. And just a small amount will go a long way; stevia is almost 300 times sweeter than sucrose. Stevia now comes in liquid and powder forms, and can be used in baked goods. But, like saccharin, some users cite a bitter aftertaste akin to licorice. Stevia has yet to be evaluated by the Food and Drug Administration.