Metabolic factors in the control of energy stores.

We have examined some of the factors involved in the control of food intake and integrated the data using methods of systems analysis from biomedical engineering. The central hypothesis is that energy stored in the body is a regulated variable. Alterations in the quantity of stored calories initiates changes designed to restore the store of calories to its original level. These responses are both short-term and long-term in nature. They involve integrating data on the quantities of protein, carbohydrate, and lipid stores in the body, probably through such feedback signals as amino acids, glucose, glycerol, and free fatty acids.