Awakening cortisol response

There is a reason why most people have little or no appetite on waking: the human body clock and the production of cortisol. Cortisol is an adrenal hormone produced cyclically: levels start to rise between 3 am and 6 am, and within thirty to forty minutes after waking, most people experience a two- to three-fold surge in circulating levels. In what is termed the ‘awakening cortisol response,’ cortisol mobilizes glucose and promotes gluconeogenesis, the manufacture of glucose from fat and protein.