Possible, but I would tend to bet its just a high sugar and sweetener diet more than anything. Obesity is not uniform at all. In pre covid days of seeing many people, I would rarely see anyone who is obese (northeast american), but that's because I'm in an upper middle class bubble. These days I'm pretty good about avoiding heating up plastics and what not. Growing up it wasn't on our radar at all. Point I'm trying to make is plastic exposure is pretty high for all populations, whereas diet varies tremendously by social class, and the composition of it has changed significantly since the 80s.