A healthy diet includes preparation of food and storage methods that preserve nutrients from oxidation, heat or leaching, and that reduce risk of food-born illnesses. Registered dietitian nutritionists (RDs or RDNs) are health professionals qualified to provide safe, evidence-based dietary advice which includes a review of what is eaten, a thorough review of nutritional health, and a personalized nutritional treatment plan. They also provide preventive and therapeutic programs at work places, schools and similar institutions.
Clinical in this sense refers to the management of patients, including not only outpatients at clinics, but also (and mainly) inpatients in hospitals. It incorporates primarily the scientific fields of nutrition and dietetics. It aims to keep a healthy energy balance in patients, as well as providing sufficient amounts other nutrients such as protein, vitamins, minerals.