If you're working in the political or public policy arena, or trying to understand events there, then the "driven by powerful global corporations" perspective can be useful. Ditto if you happen to be dealing with astroturf or other dirty tricks by those corporations. But otherwise - the "powerful corporations" perspective can easily to lead to a bit of performative activism (ranting against the giant evil yada yada)...then shrugging helplessly and changing nothing.
The underlying problem is that humans are designed/evolved[1] for environments where UPF's were (at best) extremely rare...but caloric malnutrition was always a Top 3 cause of mortality. If the giant corporations were handwaved out of existence - but food was still extremely cheap and available[2], we would still have plenty of UPF health issues. Candy, chips, cookies, ice cream, soda, & such are easily produced at very small scale. Ditto their ingredients. And the ancient lizard/snake[1] in the human brain, running algo's brutally selected for avoiding starvation, would still find those foods far too tempting.
So, for 99% of people, you need simple messages about mature individual responsibility. Because being a human in much of the modern world is like having a weakness for strong drink when you live one short block from LiquorMart.
[1] Pick whichever one works for your situation. This is public health - if you get sidetracked into God vs. Science arguments, that's a Mission Failure.
[2] By historical standards, that is the situation in much of the modern world.
