That's just my guess, tbh. I don't have proof outside of millions of anecdotal reports of people saying exactly what I'm saying here, and some studies showing that adenovirus-36 causes weight gain and became endemic in the 80s.
I'd guess that medical researchers will continue to say it "slows the stomach" or some bullshit for the next 20 years before "discovering" some serious upstream endocrine deficit in the people who benefit the most from it.
2/