I'll bring out a tray with 12 coffees on it and give some to the customers who ordered regular, others to the ones who ordered decaf. But they're all decaf.
Further analysis showed that this association, which remained relatively stable by age and body weight groups, was largely accounted for by intake of decaffeinated coffee rather than regular coffee.
That may explain why in that new Harvard study, those drinking decaf coffee but not tea beverages also showed a reduced diabetes risk, though it was half as much as those drinking caffeinated coffee.