Note: “Epidemics” by definition are contagious diseases spread by an infectious agent, so what they are talking about is not an obesity epidemic. Although it sure pulls the emotional heartstrings.
Gee, haven't you seen the "studies" that purport to show obesity is contagious?
Last one I saw even claimed that people who correspond, without ever meeting, are even MORE likely to "catch" obesity from the obese correspondent, than from someone close to them!
That is in addition to the genetic component, and the nurture component, and the low self esteem/depression component, and the....