Surgery is just a bandaid on a systemic problem. We still don't even know why we are obese! Certain groups say carbs are the devil (what about Japan, China who eat a lot of rice and keep their obesity rates very low?). Other groups say it's saturated fats (what about the thousands of years history we have of eating fats? Obesity is a very recent problem).
You will probably get fatter living in a suburb driving everywhere rather than say NYC. But that's not enough to explain the difference between countries.
What about pollutants? The food, the water, the air, the feed for animals, the antibiotics, pesticides, seed oils, microplastics?
I can't recommend anyone to try it since not everyone may be able to handle it. But it was an amazing experience I don't regret at all.