MS = Masters of Science
RD = Registered Dietitian
LD = Licensed Dietitian
In the U.S., one cannot call themselves a dietitian unless they have passed the American Dietetic Association’s national registration test. The American Dietetic Association requires a 4 year college degree in nutrition and an internship or pre-approved practical experience in order to take the national registration exam. Further registered dietitians must accumulate 75 hours of continuing education every 5 years to stay registered.
At this time, 46 states license who can provide nutrition counseling and call themselves a dietitian or nutritionist.