A social contagion is a process where the network in which people are embedded, influence their behaviors.  The idea of obesity being socially contagious is not new.1,2,4 The idea is this: If you live around people who have healthy behaviors, you might be influenced to have healthy behaviors. However, if you live around people with unhealthy behaviors, you might follow suit - thus increasing your risk of obesity. It has been shown, for example, that...