A dietitian is a professional nutritionist—an educated food and nutrition specialist who is qualified by training and examination to evaluate people's nutritional health and needs. Most dietitians are registered and are referred to as RDs. To become an RD, a person must earn an undergraduate degree in nutrition, food science, or food management, including courses in several other related subjects (chemistry, anatomy and physiology, management, psychology, etc.); complete a 900-hour internship; pass a national exam administered by the Commission on Dietetic Registration (the credentialing arm of the American Dietetic Association), and maintain up-to-date knowledge and registration by participating in required continuing education activities, such as attending workshops, doing research, taking courses, or writing professional papers.

Administrative dietitians are sometimes called dietary directors. They are entrepreneurs, disturbance handlers, resource allocators, and negotiators who work in local health departments or manage the clinical and food service systems in hospitals, correctional facilities, or long-term care institutions. Clinical dietitians or nutrition managers provide patient care in hospitals and in outpatient clinics especially related to diabetes and cancer. Nutrition-support-team dietitians coordinate nutrition care with other health care professionals; they may work in teaching hospitals, outpatient clinics, or in pediatric and diabetes clinics. In school food service, dietitians manage the overall operation, including the purchasing of food. In the food and pharmaceutical industry, dietitians conduct research, develop and market products, and represent companies at various food and health shows.

Some states require people who provide nutrition advice to be licensed, but not necessarily registered. Others allow anyone to use the title nutritionist. However, the title registered dietitian is usually used only by those who have completed the appropriate course work. The purpose of registration is to protect the health and welfare of the public by encouraging high standards of performance.

Delores Truesdell


Hudson, Nancy R. (2000). Management Practice in Dietetics. Belmont, CA: Wadsworth.

Whitney, Eleanor N., and Rolfes, Sharon R. (2002). Understanding Nutrition, 9th edition. Belmont, CA: Wadsworth.