GEN-ERIC News

Our body’s 24-hour internal clock, or circadian clock, regulates the time we go to sleep, wake up and become hungry as well as the daily rhythms of many metabolic functions. The clock – an ancient molecular machine found in organisms large and small, simple and complex – properly aligns one’s physiology with one’s environment. Now, for the first time, a Northwestern University and Evanston Northwestern Healthcare (ENH) study has shown that overeating alters the core mechanism of the body clock, throwing off the timing of internal signals, including appetite control, critical for good health. Animals on a high-fat diet gained weight and suddenly exhibited a disruption in their circadian clocks, eating extra calories during the time they should have been asleep or at rest. The study, which will be published in the Nov. 7 issue of the journal Cell Metabolism, also shows that changes in metabolic state associated with obesity and diabetes not only affects the circadian rhythms of behavior but also of physiology. Probing beyond the behavioral level, the researchers observed actual changes in genes that encode the clock in the brain and in peripheral tissues (such as fat), resulting in diminished expression of those genes.