Wake Up and Smell the Coffee: Caffeine Harms Your Health

MORE than 220 million people worldwide have diabetes and the links that have been revealed between diabetes and the consumption of caffeine beverages (especially coffee) are of monumental importance when it is acknowledged that more than 80% of the world’s population consumes caffeine daily.

Therefore premature attributions of cause and effect should not be used to justify recommendations in favor of coffee drinking as beneficial to health, especially given the broad range of adverse effects attributable to caffeine

Indeed, a growing body of research suggests that caffeine disrupts glucose metabolism and may contribute to the development and poor control of type 2 diabetes. A review article in the inaugural issue of Journal of Caffeine Research examines the latest evidence, contradicting earlier studies suggesting a protective effect of caffeine.

In the lengthy review, James Lane of Duke University describes numerous studies that have demonstrated caffeine’s potential for increasing insulin resistance (impaired glucose tolerance) in adults that do not have diabetes, an effect that could make susceptible individuals more likely to develop the disease.

In adults with type 2 diabetes mellitus (T2DM), studies have shown that the increase in blood glucose levels that occurs after they eat carbohydrates is exaggerated if they also consume a caffeinated beverage such as coffee. This effect could contribute to higher glucose levels in people with diabetes and could compromise treatment aimed at controlling their blood glucose.

Common sense suggests that those individuals who are heavy coffee drinkers probably consume little or none of these other beverages. The apparent benefits of coffee drinking may simply be due to an avoidance of the sugar-sweetened alternatives.

See my full post here

well, but on the other side, coffee contains other chemicals like chlorogenic acid which actually lowers BG. And there was a study in Diabetes Care couple years ago which reported that people who drink coffee regularly have a lower risk of getting T2DM.
Personally I think there is a HUGE difference between caffeinated sodas full of sugars or artificial sweeteners and a good cup of high-quality coffee.
Yes, caffeine itself does raise blood sugar because it raises the level of contraregulatory hormones (epinephrine, cortisol) and in higher doses the diuretic effect may also contribute to higer BG.
what I would say about drinking coffee is “all in moderation” :o)