LIMA --The friendly policeman had some good advice. We had asked him where to find a group of restaurants at the Mistura food fair. He pointed the restaurants out on a map and then added, "Don't eat too much."

That is the temptation, especially at Mistura, where the gods of Peruvian food descend once a year to serve their specialty plates to the masses. And Peruvians, alongside foreigners, do turn up in large numbers for the event, now in its third year in Lima, Peru's bustling capital.

Founded...