A trip to any U. S. major theme park ought to do the trick, preferably one of the ones around Orlando.

It seemed to me that we, meaning the US as a whole, have been building better habits.

I hesitate to pull the "you live in a bubble" card, but I think it applies here. If I looked around me here in Seattle, I might agree with you. Buncha fit hiker/snowboarder types driving Subarus on their way to the xTREME Mudfest This Is Sparta Run Sponsored by Rockstar Energy Drink. You have nothing in your profile for me to go on, so I'll go with assuming you're a 20/30-something bro living around SV who's into running/biking/whatever like all of your friends. You look around and go, "obesity problem? What obesity problem?"

Then I hop on a plane to visit my parents in Florida, and the bubble pops. O...M...G, when did children turn into such butterballs? Oh, that explains it: look at their parents. Pictures of friends in the Midwest? Same thing: when did my classmates get so fat? Again, I don't know your background, but if you're basing your opinion on what you've seen on the west coast, you're doing it wrong.