Now, according to a study published in the journal Sleep, it appears getting a good night’s rest also protects against diabetes. The study, authored by James Gangswich, PhD, of Columbia University in New York, found that adults who snoozed five hours or less a night were significantly more likely to develop type II diabetes than those who slept for seven hours. Why? Sleep deprivation’s potential to increase body weight increases diabetes incidence, says Gangswich, and so does late-night snacking. There’s also evidence that inadequate sleep decreases glucose tolerance and utilisation, and ramps up nervous system activity and the production of the stress hormone cortisol – in other words, the longer we stay up, the less efficient our bodies become at processing blood sugar fat.