Food wasn't meant to be kept forever on a shelf. With all of the crud they put into the ultra-processed foods, I'm not surprised what they have been linked to.
I remember when the low-fat craze started & all of the products that came out then. I didn't like the taste & everything seemed to me to be either sweeter or saltier. I also found out that certain foods started to disagree with me back in the late 80s/early 90s & I think it was all due to the preservatives.
I found the time to cook when I got home from work & it was cheaper for us when we were first married. I kept doing it because I didn't like the flavor of the food that was in the stores. Now the extras go into the freezer for leftovers later in the week.
Certain foods didn't agree with me anymore & I think it was due to the additives & preservatives they used. Instead of buy the frozen or fresh pie dough, I made my own. Same for a lot of the other things that I remembered Grandma making, so why not do it myself. Her food sure tasted better to me.
We buy our beef/pork from local farmers. I'm also lucky to have a bulk-food store has a lot of organic/non-gmo flours, cane sugar, sorghum, molasses & a lot of other products that we use.
When I do buy food in the stores in cans or boxes (not highly processed), I look at the ingredients to see what is it the pasta, canned goods, etc. I found Keystone Meats canned beef, pork & chicken that only contains meat & sea salt at Walmart. It's really good & is nice to have on the shelf for quick meals or in case of emergencies like if the power is out.
I do a lot of canning & try to put up enough for two years at a time when I do it. This year was tomatoes & homemade ketchup. Last year I did peach jam, apple pie jam & dilly beans & still have enough to last me until next year. Some veggies/fruit I'll put in the freeze dryer & store in canning jars after getting rid of the air with my seal-a-meal.