Is there a circadian component to hunger?
Yes, absolutely. A major focus of understanding obesity, diabetes and other metabolic disorders are targeted to understanding the circadian (and other cyclical nature) systems in neurobiology and endocrinology. I can speak within the study of diabetes, there is an observed diabetic "dawn effect" in which there is an early morning (dawn) spike in blood glucose. The exact mechanism for this spike in blood glucose is not fully known, but the general circadian nature is intriguing and would suggest a dominant hormonal cause.

Some other review articles may be found here. An overall review of homeostatic balance as it relates to the central nervous system and apetite regulation. The second review more closely focuses on the biochemistry and endocrinology of central and peripheral regulation on food intake and physical activity.


Berthoud HR, Morrison C. The brain, appetite, and obesity. Annu Rev Psychol. 2008;59:55-92.
Lenard NR, Berthoud HR. Central and peripheral regulation of food intake and physical activity: pathways and genes. Obesity (Silver Spring). 2008 Dec;16 Suppl 3:S11-22.