I dont live in the US, but we are seeing more problems with obesity here in the UK as well and its quite worrying when you see children are very overweight, they have little chance of rectifying that and it will probably get worse as they get older.

While I dont think overweight people should be shamed, I do also agree with you that pretending its normal is also wrong, and if thats whats happening in the US then there seems to be little hope of resolving the issue. I do think people have become especially image concious, and this is the wrong approach, its not about being attractive (though that is a side benefit), its about feeling good, both physically and emotionally; excercise and good food makes you feel better.
And I suppose thats where the problem comes, if a lot of people feel good, there is no need for legal highs like sugar/fat packed foods, and no market for anti-depressant drugs etc.