You know that skipping the gym and following a lousy diet are bad for your blood sugar, but there are some other habits linked to diabetes that might surprise you.

Watching television

A recent Australian study of more than 4,000 men and women found that the more time they spent as couch potatoes, the greater their risk of having high blood sugar, even if they exercised regularly. The strongest risk was associated with a little more than 2 hours of daily viewing for women; 2½ hours for men.

Not sleeping enough

Research presented at a June 2009 conference backed by the American Academy of Sleep Medicine suggests that sleeping for five or fewer hours a night significantly increases a person's risk of type 2 diabetes. And a 2008 study found that depriving healthy young adults of deep sleep disrupted their bodies' ability to regulate blood sugar. In addition, recent research suggests that type 2 diabetes may be associated with a genetic mutation that affects the sleep-inducing hormone melatonin.