https://pubmed.ncbi.nlm.nih.gov/35658669/

https://pubmed.ncbi.nlm.nih.gov/25804833/

^—- Conclusions: The consumption of ultra-processed products (i.e. foods with low nutritional value but high energy density) has increased dramatically in Sweden since 1960, which mirrors the increased prevalence of obesity. Future research should clarify the potential causal role of ultra-processed products in weight gain and obesity.

So, the last one has a quantitative definition that could be used for a preliminary ban.

Also, all those articles link many more. One click deep will provide a dozen concurring studies. I didn’t feel like adding more links.