The Food and Drug Administration (FDA) has issued a guidance document that identifies eight ingredients that the agency has determined meet the regulatory definition of “dietary fiber.” Specifically, FDA has recognized the following ingredients as meeting the dietary fiber definition: (1) mixed plant cell wall fibers; (2) arabinoxylan; (3) alginate; (4) inulin and inulin-type fructans; (5) high amylose starch (resistant starch 2); (6) galactooligosaccharide; (7) polydextrose; and (8) resistant maltodextrin/dextrin. In this guidance document, FDA also announced that it intends to extend enforcement discretion regarding the declaration of these eight isolated or synthetic nondigestible carbohydrates (NDCs) as a dietary fiber on Nutrition Facts and Supplement Facts labels pending completion of a formal rulemaking to revise the dietary fiber regulation to reflect these ingredients. In addition to the guidance document, FDA has also published a review of the scientific evidence on the physiological effects of these NDCs, 2/ and has issued responses to several citizen petitions requesting that certain NDCs be added to the “dietary fiber” definition.