Fructooligosaccharides (FOS) are short-chain polymers comprised of D-fructose and D-glucose, which are not metabolized by the body like simple sugars are, and are therefore considered non-digestible oligosaccharides. They occur naturally in bananas, garlic, Jerusalem artichokes and certain other foods, and technically are a soluble fiber (NutriCology's FOS are derived from chicory root). FOS are effective sweeteners, being half as sweet as sucrose, yet are not absorbed and have minimal caloric value. FOS may be considered prebiotic as they selectively support the proliferation of intestinal probiotics, especially the bifidobacteria.