Metabolism is the chemical process occurring in the cells, which involves releasing energy from nutrients. Metabolism is an ongoing process and necessary in order to maintain life. The process of metabolism not only involves the digestion of foods but also involves processes which use energy, such as the contracting of muscles, temperature regulation, elimination of waste and circulating of blood.
In Our Own Words
Metabolism is a complex process, consisting of countless chemical reactions that act to build things up, such as in fat storage, or break things down, such as in the digestion of food or muscle for energy. Metabolism is the sum total of all of these building up (anabolic) and breaking down (catabolic) reactions. The body uses that energy for a variety of essential functions including breathing, digesting and eliminating food, controlling body temperature and circulating blood. The process of metabolism is constant. Although the process is ongoing, the rate at which an individual converts nutrients into energy varies. This is known at the metabolic rate.