Evolution has selected animals that, when they have access to foods with high caloric density, will gorge on them. This has been advantageous to their survival, because the history of life has been characterized by famine feast cycles for most species. Now, what UPF foods are is foods that have had most of their non-caloric content removed or been processed to increase calorie content, triggering this gorging behaviour. This is probably 80% of the obesity epidemic today. The rest is probably additives that affect our hormones that control hunger/satiety signals in the body.
In my opinion, effective regulation would control the caloric density as food as well as ban any additives that can affect hormonal hunger/satiety.
In my opinion, effective regulation would control the caloric density as food as well as ban any additives that can affect hormonal hunger/satiety.