Studies show that drinking moderate amounts of alcohol (one drink a day for women and two drinks a day for men) can actually lower the risk of diabetes, the opposite is true for people who drink greater amounts of alcohol. Heavy alcohol use causes chronic inflammation of the pancreas (pancreatitis), which impairs its ability to secrete insulin and ultimately lead to diabetes. Tobacco is equally harmful. It can increase blood sugar levels and lead to insulin resistance. And the more you smoke, the greater is your risk of diabetes. Heavy smokers who smoke more than 20 cigarettes a day almost double their risk of developing diabetes, when compared with nonsmokers.