You mentioned that caffeine was banned by the Olympic Committee. This is only on the order of a dose of several (I believe it is 1.6) grams. An 80-kilogram adult would only take a dose of around 400 milligrams (5 milligrams/kilogram of body weight). This also would have been taken roughly four hours prior to the workout. Caffeine serum levels peak around 4 hours after oral administration. They, of course, peak immediately after IV / IM administration. The sugar-sparing effects of caffeine are due to the increased blood adrenaline levels (caffeine is a mild sympathomimetic in higher doses).
Originally the IOC (International Olympic Committee) banned caffeine, but that has been reversed. The amounts of caffeine you mention (400 milligrams) are about twice the maximum recommended for anyone. At that rate, the person will probably experience caffeinism.