EXPERT IN FOOD AND NUTRITION

As defined by the Academy of Nutrition and Dietetics, "Registered dietitian nutritionists -- RDNs -- are the food and nutrition experts who can translate the science of nutrition into practical solutions for healthy living. RDNs use their nutrition expertise to help individuals make unique, positive lifestyle changes."

EXPERIENCED NUTRITIONAL COUNSELOR

"Anyone can call themselves a nutritionist, but only a registered dietitian (RD) or registered dietitian nutritionist (RDN) has completed multiple layers of education and training established by the Accreditation Council for Education in Nutrition and Dietetics (ACEND). In addition to holding a bachelor's degree, an RD or RDN must fulfill a specially designed, accredited nutrition curriculum, complete an extensive supervised program of practice at a health care facility, foodservice organization or community agency and pass a rigorous registration exam," according to Karen Ansel, MS, RDN, CDN, for the Academy of Nutrition and Dietetics.

SPECIALIST IN ONCOLOGY NUTRITION

Beyond the core requirements to become a registered dietitian, RDs with extensive practice experience in a specialty field of practice may also pursue additional board certification. To become board certified in oncology, a dietitian needs a minimum of 2000 practice hours and must also pass a rigorous certification exam.