Number 9 and number 4 can’t both be right. It’s not like the when the SHTF that suddenly wind sprints are going to be mandatory and all fat people are going to keel over from heart attacks. Fat is just calorie storage, not that most people will stay fat that long in a true SHTH scenario, but the fat will have an short term advantage.
Fat folks bury their skinny peers in famine. However, it has long been known the most important predictor of survival on the battlefield is physical fitness.