How McD's lost Phelps to Subway

Michael Phelps volunteered throughout his domination of Olympics coverage that he was a diehard McDonald's fan. Now he's signed on as a pitchman for the arch-rival Subway chain. How did the Golden Arches miss a chance to enlist the Man of Gold in its marketing efforts? A perception of health apparently appeals to more than the weekend-warrior set. See Advertising Age's full explanation.