Fortaleza, Brazil

CELENE da Silva, 29, is one of thousands of door-to-door vendors for Nestlé, helping the world's largest packaged food conglomerate expand its reach into a quarter-million households in Brazil's farthest-flung corners.

As she dropped off variety packs of Chandelle pudding, Kit-Kats and Mucilon infant cereal, there was something striking about her customers: Many were visibly overweight, even small children.