A registered dietician (RD) is a food and nutrition expert who has successfully completed a minimum of a bachelor's degree at a US regionally accredited university or college and course work approved by The American Dietetic Association (ADA); an ADA-accredited or approved, supervised practice program, typically 6 to 12 months in length; a national examination administered by the Commission on Dietetic Registration; and continuing professional educational requirements to maintain registration. Source: The American Dietetic Association. Becoming a Registered Dietitian - a food and nutrition expert. Chicago, IL: The American Dietetic Association, July 1997.