A dietitian is an expert in dietetics; that is, human nutrition and the regulation of diet. A dietitian alters their patient's nutrition based upon their medical condition and individual needs. Dietitians are regulated healthcare professionals licensed to assess, diagnose, and treat nutritional problems.

Dietitian nutritionists use nutrition and food science to help people improve their health. Nutrition and dietetic technicians work with dietitian nutritionists to provide care and consultation to patients. Both dietitian nutritionists and nutrition and dietetic technicians may also provide general nutrition education.

Dietitians provide food and nutrition information, and support people to improve their health. They provide advice on nutrition-related matters. Dietitians can also change diets to help manage conditions such as:

• diabetes
• heart disease
• overweight and obesity
• cancer
• food allergies and intolerances.