>>it’s a scientific fact, and it’s backed by years of studies

Sorry, but you lost me at "scientific fact".

There are no 'facts' in science, just things that, try as they might, scientists have been unable to disprove. I'm not sure what anyone can get from reading years of studies without understanding how science works.

That said, we're starting to have an understanding on the cellular level of how insulin resistance starts, and IR is most probably the common thread, with overweight as one of the many symptoms.