Metabolism:
Our bodies get the energy they need from food through metabolism. The chemical reactions in the body’s cells convert the fuel from food into the energy needed to do everything from moving to thinking to growing.
Food sap containing nutrients is absorbed into the blood, which transports them to the cells. After they enter the cells, other enzymes act to speed up or regulate the chemical reactions involved with metabolizing these compounds. During these processes, the energy from these compounds can be released for use by the body or stored in body tissues, especially the liver, muscle, and body fat.
In this way, the process of metabolism is really a balancing act involving two kinds of activities that go on at the same time – the building up of body tissues and energy stores and the breaking down of body tissues and energy stores to generate more fuel for body functions.