As someone who moved to Europe and also lost quite a bit of weight, the bigger factor was eating out is hella more expensive here. Junk food is also more expensive though still relatively cheap, at least in the Netherlands.
But yea, the EU does a lot better job policing what goes into food and it shows. Fruits and vegetables and meat that I buy here spoil within 2-4 days (and 4 is pushing it)! I had to adjust my purchasing habits because it would go bad before I could eat it all.
The public transportation and push to cycle and walk definitely helps, but at least where I live in the south, most families still own at least one car. The difference is that they only use it to drive to work and for trips. Any errands are done on foot or on a bicycle.
Go to Europe and eat home cooked meals there. Your health will improve