Night Eating Syndrome and Circadian Rhythm

People with the night eating syndrome (NES) have morning anorexia, evening hyperphagia, and insomnia followed by eating. A trio of researchers at the University of Pennsylvania recently reported at the 2004 International Conference on Eating Disorders that altered circadian rhythm may play a role in NES. In their study there was no difference between the total energy intake among 46 overweight and obese persons with NES and 43 matched non-overweight control subjects. However, but the pattern of energy intake differed greatly between the two groups. Those with NES had more nocturnal awakenings than did controls, and they awoke from sleep earlier during the night than did control subjects. Food intake after the evening meal was more than three times higher in NES subjects than in controls. According to the authors, the shift in energy intake of the night eaters suggests a phase delay in energy consumption in relation to sleep-wake times. According to John P. O’Reardon, MD and colleagues, this suggests that NES may involve a dissociation of the circadian control of eating in relation to sleep. In another study, Dr. L. Q. Qin and colleagues observed altered endocrine patterns among medical students who lived either a diurnal life or a nocturnal one. The researchers reported that the nocturnal lifestyle led to impairment of the normal insulin response to glucose (Life Sci 2003;73:2467).