Ryan is just obsessed with this anecdotally. He works out a lot and so has disdain for those who he considers unhealthy "by choice".
Paul Ryan is one of those special kinds of idiots who thinks that some version of Rand's Objectivism is not only valid and universally applicable, but that the basis for objectivity is his own empirical experience, and that any relation of an experience counter to his own must be either due to a lack of intelligence/understanding, misinformation, or else be the willful fabrication of a communist.