Dietitians and nutritionists counsel patients on nutrition issues. Dietitians and nutritionists are experts in the use of food and nutrition to promote health and manage disease. They advise people on what to eat in order to lead a healthy lifestyle or achieve a specific health-related goal. A dietitian (or dietician) 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.