For me, it has to be the UK since British food tends to be heavily processed along with a fixation on fish & chips, bangers & mash, pies and pastries with high fat content (most feature at least a fried item beside them, whether it’s an English breakfast with a hash brown) but not on the level of unhealthy to that from American cuisine.
Italy, without a doubt.
I love the story about how all the studies about people in Italy living longer from their olive oil consumption turned out to actually be massive benefits fraud with people claiming for elderly residents who were in-fact already dead.