Registered dietitians work with clients who are looking to improve their health through dietary, environment, and lifestyle interventions. A dietitian will work closely with a client using evidence-based medical nutrition therapy to understand and address their particular needs and challenges whether dealing with chronic disease, food allergies and intolerances, disordered eating or any diet-related health concern. Anyone can call themselves a nutritionist, but only a registered dietitian (RD) or registered dietitian-nutritionist (RDN) has the credentials to prove their expertise. Some RDs choose to call themselves nutritionists as well. In addition to holding a bachelor's degree, an RD or RDN must fulfill an accredited nutrition curriculum, complete over 1200 hours of supervised practice at a health care facility, and pass a rigorous registration exam.