I've never had a BMI above 19 since puberty, so I can't speak as to being overweight. However I did gain (a welcome...) 10 pounds when I moved to the US. I attribute this to:

* my workplace had free candy bars lying around (think Reese's and that kind of stuff)

* bigger portions in restaurants

* temptations for things like cookies and muffins; there were bakeries everywhere on my way to/from work

So I would suggest the opposite thing. Move somewhere with no bakeries or restaurants (rural is good), pick a health conscious workplace or lobby your boss to remove snacks from the building (dangle the health insurance prices carrot if needed). Also you can do a thing I did which is go to work by train, the station was 2 miles from the office. Easy daily workout. I ran instead of walking because the train was usually late.

In summary, you should re-arrange your life to fit your desired weight goal rather than rearrange yourself struggling every day against a life that is clearly pushing back against you.