Nutrition (also called nourishment) is the provision, to cells and organisms, of the materials necessary (in the form of food) to support life. Many common health problems can be prevented or alleviated with a healthy diet.
The diet of an organism is what it eats, which is largely determined by the perceived palatability of foods. Dietitians are health professionals who specialize in human nutrition, meal planning, and preparation. They are trained to provide safe, evidence-based dietary advice and management to individuals (in health and disease).
A poor diet can have an injurious impact on health, causing deficiency diseases such as scurvy, beriberi, or health-threatening conditions like obesity and metabolic syndrome; and such common chronic systemic diseases as cardiovascular disease, diabetes, and osteoporosis.