It does make me think we're applying bandaids over some other issue with the available foods - it's hard to imagine that everyone 50 years ago was just much better about dieting and counting calories?
Do we just have a lot more food available now? Not just bad food, but calories of all kinds? Combined with steadily automating nearly all of the hard work, I'm not surprised people get fatter these days than 50 years ago. I bet the average person today is actually much more aware of what healthy eating looks like, it's just that there aren't that many really physical jobs anymore and food is extremely cheap and plentiful for most.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10097271/#:~:text=S...
Basically incredibly tasty food became plentiful and cheap and convenient right when physical labor went away.