Metabolism in the human body involves breaking down food products and utilisation for body needs (anabolism) and also breaking down of muscle and tissue protein following exercise etc. resulting in the elimination of the waste products from the body (catabolism). Increased metabolism occurs with increased activity to cope adequately. However if a normal person has increased or decreased states of the process, one should consider disorder/malfunction of certain endocrine glands, e.g. thyroid.