Type 2 diabetes—also known as adult-onset diabetes—is rapidly increasing in prevalence in the U.S. But getting enough shut-eye may dramatically slow your risk of this chronic killer.

Experts at the University of Chicago Medical Center say getting deep restorative sleep—or slow-wave sleep—is essential to regulating blood sugar levels in the first study to link lack of sleep to diabetes risk. After only three nights without deep sleep, study participants needed more insulin to dispose of the same amount of glucose (blood sugar), thus upping their diabetes risk.

Experts equated the lack of sleep to carrying around an extra 20 to 30 pounds.

Want to reduce your risk? Get at least seven to nine hours of sleep each night, with plenty of deep restorative sleep—no tossing and turning allowed.