A nutritionist is an expert in dietetics; that is, human nutrition and regulation of nutrition. A nutritionist changes the diet of his patient depending on their health and individual needs. Nutritionists have regulated health professionals who are approved to assess, diagnose, and treat nutritional problems. Dietitians and nutrition provide education and advice for complex nutritional requirements such as intravenous feeding, negative nutrients, nutritional supplements, food safety storage, diet and drug interactions, and more. Patients can consult online with a dietitian and nutrition for diet counseling.