Researchers at Israel’s Weizmann Institute have detailed for the first time how human biological clocks work in tandem with intestinal gut bacteria to control blood sugar levels. Digestion suffers when the schedules of the gut bacteria are interrupted by late-night wakefulness.

http://www.timesofisrael.com/obesitys-link-to-lack-of-sleep-is-gut-wrenching-problem-study-shows/