Part of the difference is that, in the UK, the doctors have been treating my wife's problems as honest medical problems and not just beating the diet and exercise drumbeat regularly. My wife spent a good part of the last year essentially bed ridden. The US doctor performed test after test to find out what was wrong. She eventually prescribed some medication for my wife which made her violently ill, but the doctor promised her body would acclimate to the medicine and that, in a few months, she's be able to walk again.
Since coming to the UK, we've discovered that the battery of blood tests that were performed back in the USA was actually just the diabetes test being performed over and over again because the test kept coming back negative. The medicine prescribed was actually a drug for the treatment of diabetics, despite the doctor having twelve negative blood tests on my wife for diabetes.
Instead, the UK doctor considered the possibility that there was something wrong with my wife besides just being fat. After a week on her new medicine, she was starting to walk without a cane again. In the past two months, she's lost thirty pounds. It's amazing how much more exercise you can get when you're not bedridden. Next week, we're seeing a GI doctor because the UK doctor realized that A) my wife would lose more weight if she ate more salad, B) my wife would eat more salad if she didn't always violently vomit it back up six hours later, and C) regurgitating food eaten more than fours hours ago isn't normal. The doctors in the USA never could seem to figure out B and C, so they would just double down on A.
By the way, in case you think that it was just that one doctor, that's not even our worst experience with it. About a decade back, my wife went to the emergency room after getting stabbed. The nurse told her the the problem would go away with diet and exercise. A stab wound. Thankfully, she caused enough of a scene to get a second opinion and the STITCHES that normally accompany stab wounds.