Although the terms are sometimes used interchangeably, there are differences between registered dietitians and nutritionists to keep in mind when you’re seeking nutrition advice. Dietitians must undergo rigorous academic and professional preparation. RDN coursework includes food systems management, nutrition, chemistry, biology, and other science, nutrition, and food systems-related courses. In addition to earning a college degree, RDNs must complete an accredited, supervised internship program. They also must pass an exam from the Commission on Dietetic Registration and, if required, receive licensure from their state. RDNs regularly engage in continuing education courses in order to maintain certification.