But there's new research about our favorite pick-me-up that may "perk" up its image: a study that finds drinking coffee cuts the risk of a disease now plaguing adult Americans: Type 2 diabetes.
"We found that heavy coffee consumption substantially reduced the risk of Type 2 diabetes in both men and women," said Dr. Frank Hu of the Harvard School of Public Health.
By "heavy" coffee consumption -- researchers mean 6 or more cups a day -- but what they found was startling. Among the thousands of men and women followed for the study, male coffee drinkers had a 50 percent reduction in diabetes risk. The risk for women was reduced by 30 percent.
Even those who drank decaf saw some benefit.
"Contrary to what was initially thought, coffee is not bad for you. In fact, it may be good for you," said Dr. Peter Martin.
The reason, according to Dr. Martin, who heads up the Institute for Coffee Studies at Vanderbilt University, is that coffee is not just about caffeine.
It's a complex brew of many compounds, among them something called chlorogenic acid, that may ward off Type 2 diabetes
"It increases the body's capacity to dispose of glucose, which is sugar in the blood," Martin said.
The study results are not an invitation to start drinking six cups of coffee a day if you don't already -- it will still keep you up at night. But at least now you won't be kept awake worrying that the coffee you're drinking is only doing you harm.