In 1969, Hervey hypothesized the long-term stability of body weight is actually mediated through the regulation of blood steroid concentration. We suggest that glucocorticoids are the regulated variable the concentrations of which entails bodyweight stability. A descriptive model of this regulation is proposed. Because steroids are soluble in lipids, it follows that their concentrations in the body depend in part of the volume of lipids stored. Low fat stores increase the glucocorticoid concentration in the blood, and conversely high fat stores lower the glucocorticoid concentration. Body weight could thus be the end product of the glucocorticoid levels. The set-point for body weight would be adjusted by intracerebral CRH.