The initiation and cessation of feeding behavior is explained on the basis of the ischymetric hypothesis (from ISCHYROS meaning "Mighty One" or power). Cellular production of power or "Metabolisme de Fond" (MF) is measured continuously in terms of total body metabolism minus the metabolic costs of locomotion. A drop in MF signals the onset of eating. Eating initiates a rise in MF and when this signal peaks, the feeding process stops. Control of satiation is described in terms of recent neurophysiologic and neuroendrologic factors that influence MF.