More Americans Say They Weigh 200 Lbs. Or More This Decade
news.gallup.com
news.gallup.com
According to this Time article, American heights increased in previous decades but pretty much stalled out: https://time.com/4423803/how-tall-100-years-height/ So I guess the results are pretty much the same even without the height info.
That said, I suppose if a population generally becomes fitter and increases muscle weight, the overall BMI could become unreliable for the same reason it's not a great tool at the individual level.
I’d say fast food isn’t the only culprit, normal restaurant portions are enormous too with the exception of a few health-focused salad chains.
Consumption of restaurant food has continued to increase over the last 30 years as the country gets more and more wealthy.
There are probably a lot of factors involved here of course.