A 100% natural sugar alternative that can be used 1 to 1 in place of sugar and will NOT increase fat storing hormones. Lean Sweet is 100% pure xylitol (zy-la-tall). Humans make several grams of xylitol in their bodies daily and it is naturally occurring substance in fruits. Xylitol is also known as birch sugar and it is made from the bark of birch tress or the hulls of corn cobs. Aside from its use as a sugar alternative, xylitol has many other health benefits and has been shown to decrease cavities, reduce ear infections and sinus infections, and possibly help maintain muscle and bone mass.