This time, I want to see mice/rats given coffee or decaf.

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.

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.