I read about this in Bicycling Magazine last month. Fortunately, I blocked it out of my mind so I didn't actually do it. The article in the magazine said that the winners usually end up with a
negative net time. I'm not the fastest rider, but I think most people would take at least an hour and a half to two hours to do the ride. That is a lot of donuts to eat.
http://www.ohiocycling.info/OBEC.html#Anchor-Saturda-42450
TOUR DE DONUT. Greenville. Ride the 30-mile, rolling course for time and then, for each donut you eat, your time will be reduced by five minutes! Could Homer Simpson win? Ride to eat, eat to ride. Prizes to overall net time winners in several categories.