I always said it was evil stuff, and now I've got science in my corner to back me up: drinking decaffeinated coffee may be harmful to heart health.
The magnificently wrongly-acronymed Caffeine And Lipoprotein Metabolism study led by Dr. Robert Superko of the Fuqua Heart Center in Atlanta compared the effects of decaf and real coffee on 187 volunteers. They each got three to six cups of black coffee per day, same brand brewed the same way.
Then the researchers did a lot of bloodwork, checking various heart-disease indicators: blood pressure, heart rate, body-mass index, cholesterol, triglycerides, HDL (coyly known as "good cholesterol"), insulin level, blood sugar, fatty acids, apolipoprotein B (a sign of "bad cholesterol"), and the annoyingly virtuous HDL2 ("really good cholesterol" -- I'm not making this up).
Here's the money quote:
"Researchers found no significant changes among the three groups’ levels of blood insulin and glucose, or other major risk factors."
The study went on to find a slight (but real!) positive correlation between decaffeinated coffee and the bad cholesterol. Translated into bad science journalism-ese: DECAF KILLS!
Tell that to the next irritating health fascist who tells you not to drink so much caffeine. Why, coffee's so healthful that in Brazil they're giving it to children for free.
It's possible to make a case that modern civilization as we know it was built by coffee. In the Middle Ages, people drank wine and beer, pretty much exclusively. Much of the history of medieval Europe makes a lot more sense when you realize it was populated largely by drunk teenagers.
Then Europe discovered caffeine. Boom! The Scientific Revolution. The Enlightenment. The Industrial Revolution. Heavily-caffeinated Europeans built global empires to ensure reliable supplies of tea, coffee, sugar, and chocolate. Without coffee, we'd still be fatalistic drunken peasants.