Run. Eat a Doughnut. Run.

This weekend in Raleigh, N.C., some 8,000 runners are expected to line up for a road race, run through town and — eat doughnuts. “Disgusting” and “gross” is how Sarah Gilbert, 43, a book publicist from Raleigh describes how she felt after completing the Krispy Kreme Challenge in 2012, in which she downed four doughnuts…