We wouldn't be able to physically care for them. That's what they haven't considered. The sheer numbers. There aren't enough healthy people to care for the unhealthy. And the healthy just aren't strong enough to deal with their increasing weights. So...they're gonna die a whole lot sooner then they are now. And medical science won't be able to save them. The two or three generations of fatties that are crushing the economy/health care system will die off and this situation will stabilize because people will realize that survival is not tenable under these circumstances.  Unfortunately, the rest of us will suffer until then because people are lazy, greedy and gluttonous.