Personally I don't like this stereotype.
Have you ever compare us with other nations? IS it really true?
One idea of mine:
Poorer people have to buy cheaper food. Cheap food tends to be more fattening and unhealthy than more expensive alternatives.
In a society in which time and money are king, it's no surprise that fast food is also
king.
May we blame fast food as usual?
SO, how fat are you?
Examining old b&w photos from turn of the (previous) century's "fat man/lady" from circuses and sideshows says it all.
"...Barnum’s fat man was 275 and theirs just breaks 280." -Real weights of some period "fat men." 280's about the average NASCAR fan now.
Meanwhile, this is now the 'world's fattest woman'
Weighs about as much as 4 circus sideshow 'fat ladies.'