My friends made me fat
The Washington Post has a video from Harvard researchers who find that social networks spread obesity "like a real epidemic". "Obesity," they conclude, "is not an individual phenomenon, but a collective phenomenon" as well. Those researchers might be interested in extending their study to the Third World, where social networking among the elites and upwardly mobile can sometimes reach the intensity of a mania. It's easy to see how an endless round of dinners, coffees, cocktail parties, etc can bulk a person up very quickly. But the Third World offers an opportunity to study social networking among the poor as well, and here, I think the Harvard researchers may find the correlation doesn't hold. Members of prosperous social networks in Third World countries have the money to stuff themselves, but people at subsistence poverty, however convivial, run up against the hard problem of finding anything to eat.
In some countries, obesity is actually attractive because it is directly correlated to economic success. Rail-thin man with washboard abs in a Third World setting are likely to be day-wage workers or dirt farmers. And when you realize that "party time" means boiled sweet potatoes and swamp cabbage, the attractiveness of thin men diminishes fairly quickly. But ponderous men with shiny white shoes, hung about with jewelry and possessed with a mouthful of gold teeth are courtship signals of prosperity.