If you read the work written by Dr Xand van Tulliken and other writers in the field. They put the blame, not on what we eat but its constituents. the processed ingredients, food elements we never ate before. all those 'modified', emulsifiers, 'hydrolised' etc etc.
Other researchers into the human biomes have reiterated what is being said. It is impossible to completely eliminate these products from our lives, but by home cooking from fresh ingredients can reduce it, as will, ideally, shopping organic, not always possible or affordable, but shop for meat in farm shops where they rear their meat to high welfare standards, many of their other meat products will be free or nearly free of the UPF incgredients.
When meat costs mroe reduce portion size. i was brought up on 4oz of meat per person - and most recipes work to this portion size. I have gradually reduced portion size to 2 oz. We eat a lot of casseroles and stews and I add extra vegetables and beans to every casserole.