General

Johnxyz:
I'm 75 years old. I have seen diet plans, weight loss drugs and weight loss surgery come and go. I have personally known two people who died from taking Fen-Phen. I've seen and heard about a lot of people who have died or became permanently disabled from weight loss surgery. (They keep blaming the "old" surgery, even when the new became the old.) Basically, your body can't tell the difference between someone in a concentration camp, and someone who wants to look more fashionable. We will never see the eradication of obesity.

Delta9:
At some point obesity will be seen as a curable disease, and if you choose not to accept the cure, you'll be penalized, probably by having insurance coverage dropped. And also people will think something else is wrong with you, like a person with poor vision who refuses to simply wear glasses.
As obesity becomes less common, those who reject the cure and embrace their size will be viewed as particularly disgusting. As well as those of us who desire them. Anyone who remains overweight, people will automatically assume they must have a fat fetish. So maybe it can become a more honest world in that regard, and we can finally admit to everyone that we're fat because we want to be that way.
But also, this is probably a decade or two away.