Also, if there were suddenly a time of horrible famine, everything would go to shit (look at Venezuela). The fitter people would be able to get the resources they and their families need, like water which you can't go three days without, and those who can't get out of a chair unassisted because they're just too large would definitely suffer for it. Think about it: could you imagine a 450-pounder standing in a rationing line all day? Absolutely not. It would collapse from bad knees or sugahs or something. They couldn't scavenge effectively because that's too much effort. They wouldn't even be good for security because they'll be too busy eating everything they're supposed to protect rather than look out for intruders.