One very simple thing people can do that costs no money and they can keep buying exactly the same products they do now -- just less of it -- is stop overeating.

https://www.treehugger.com/health/overeating-terrible-planet...

As for industrial food, and how it got to be, I strongly recommend this book by Aaron Bobrow-Strain https://www.amazon.com/White-Bread-Social-History-Store-Boug...