The average person eats one-half cup of sugar a day, more than is recommended for the average person, particularly people who suffer from diabetes, insulin resistance, and Syndrome X. Unlike sugar, xylitol does not require insulin to be metabolized. Xylitol is an all-natural sugar substitute derived from birch tree bark or from corncobs. It is teaspoon-for-teaspoon as sweet as sugar, and has the added quality of binding to saliva, leaving a sweet taste lingering in the mouth. Fran Gare explains the health benefits of using xylitol rather than sugar, aspartame, saccharin, sorbitol, or mannitol.