Nutrition or nourishment (also referred to as aliment), is the supply of food materials required by all organisms to stay alive. In science and human medicine, nutrition is the science or practice of consuming and utilizing foods.
Nutritional science studies how the body breaks down the food (catabolism) and repairs and creates cells and tissue (anabolism). Thus, the activities of catabolism and anabolism together is called metabolism.
Nutritional science also examines how the body responds to food. Nutritional science investigates the metabolic and physiological responses of the body to diet.
Nutrition also focuses on how diseases, conditions and problems can be prevented or lessened with a healthy diet.
Nutrition also involves identifying how certain diseases, conditions or problems may be caused by dietary factors, such as poor diet (malnutrition), food allergies, metabolic diseases and so on .
As molecular biology, biochemistry and genetics advance, nutritional science has become more focused on the steps of biochemical sequences through which substances inside us are transformed from one form to another (metabolism and metabolic pathways).