The human body is a complex, living, biological organism that is sustained by nutrients for its continued survival. Without these nutrients, the body breaks down from weakness and disease and eventually dies. Like any living organism, the human body has to be cared for by providing it with the means to maintain the energy it needs to keep its biological functions working.
Everything that the human body can do - seeing, touching, hearing, smelling, thinking, moving, reproducing, and so on - would depend on how well its smallest unit called the cell is nourished and maintained. Since the human body consists of some 60 trillion cells (Dunne, 2002, p. 135) that are grouped together into organs, each with its own function and purpose, the whole body will be healthy and able to live for a long period of time if the cells in the body are kept in good working condition. This is what nutrition is supposed to do, to keep each cell healthy and functioning properly. Nutrition provides the body with nutrients that are chemical substances necessary to keep the cell, and therefore the body, alive. There are six types of nutrients: carbohydrates, fats (or lipids), proteins, vitamins, minerals, and water. ...