Earlier quoted context omitted.
Would "people ate less and suffered less heart diseases time ago?" qualify as C? Of course this point has the same problem of lacking details. But recognizing "modern food" as a culprit is actually less overeaching than putting the blame on a single substance that has been used for centuries.
"Would "people ate less and suffered less heart diseases time ago?" qualify as C?" No; that would fall under "no good reason". Are you sure people "ate less"? Given that we (think we) know that people of the past were also more active (although history is definitely on your side for that one), and how much more active people need to eat to sustain their activity, I would be completely unsurprised to learn that people…
My point was that, even if not exactly science, basic facts are known. Yes, I'm sure people ate less in the past. I've seen the numbers and, to a certain extent, I've seen people changing their habits in my lifetime.
This is like a tide, while many studies are focusing in a few waves. That's what my point anyway.