I've heard this objection a lot, even from folks I respect. Its ubiquity makes me wonder it is astroturfed.
The definition I have heard is "food made with ingredients or processes not commonly used in ghome Unfortunately, when I looked to leading scientific orgs, they are dithering on releasing formal definitions, but all say something like what I'd heard.
Conflicting information doesn't mean an abysmal situation. I'd argue the opposite. Everyone "knew" the sun orbited Earth.
Yes, you got me, I get paid $50 Soros bucks for every snarky post. It couldn't possibly be that "not commonly used in the home" is a vague and unhelpful definition, which varies across time and cultures. Or that these researchers still haven't explained the theoretical basis linking all these wildly different "UPF"s to the negative health consequences they're supposed to explain.
How should using processes not used at home make something harmful? If we make the same processes commonly available to use at home, will these foods become less harmful?
I know there is science around it, but the very concept looks very unscientific, it's almost like talking about "unnatural food"