If you already have a bachelor's degree but it is not in a nutrition or food science related area, you can have your college transcript evaluated by a dietetics program professional at an institution of higher education. You may only need to take a few additional courses to become a nutritionist, and you can sometimes combine this with working toward a graduate degree, as noted by the American Dietetic Association (ADA).
To become a licensed or certified nutritionist, you will have to comply with the laws of your state governing the profession. The U.S. Department of Labor notes, "Of the 46 States and jurisdictions with laws governing dietetics, 33 require licensure, 12 require statutory certification, and 1 requires registration. Specific requirements vary by state." Often the state will require you to pass an exam, but you must find out your state's requirements, as some will not permit you to work as a nutritionist or dietitian without a license.
Most states require you to obtain a license. States that require certification limit the use of occupational titles to people who meet certain requirements; individuals without certification can still practice as a dietitian or nutritionist but without using certain titles as of 2010, according to the Occupational Outlook Handbook. State registration is the least restrictive form of state regulation of dietitians and nutritionists.
To locate the licensure or certification requirements of your individual state, go to the state website and search on "dietetic license." Most state websites have information on how to apply for various kinds of licenses, permits and registrations. When applying for licensure to practice as a nutritionist or to take the required exams, you may have to pay some fees---usually in the range of $50 to $275. Also, many states require license renewals, which will also involve fees within the same range.
If you wish to become a Registered Dietitian as defined by the ADA, you will need to review the requirements detailed on that agency's website. The ADA's registered dietician program may differ from some state requirements. Also, the ADA requires continuing professional education to stay registered. Additionally, the Commission on Dietetic Registration, the credentialing agency for the American Dietetic Association, administers the assessments for and awards 7 separate and distinct credentials: Registered Dietitian (RD); Dietetic Technician, Registered (DTR); Board Certified Specialist in Renal Nutrition (CSR); and Board Certified Specialist in Pediatric Nutrition (CSP), Sports Dietetics (CSSD), Gerontological Nutrition (CSG) and Oncology Nutrition (CSO). Naturally, opportunities and salaries for clinical nutritionists increase with years of experience and additional education and credentials.