There's a huge confounder missing in your analysis which is that they're also typically quite old by the time they retire. People don't change their habits easily at that age.
I'm the same. It's just human nature to not want to expend effort. We love excuses, like - I'm too stressed, to busy etc. - but quite often, they're just that - convenient excuses.
All humans in environment A get fat, develop heart disease, and are depressed. All humans in environment B are lean, live long lives without medication, and are happy. The only logical conclusion: everyone in environment A is lazy or otherwise morally deficient.
What's with the denial? A significant portion of population of developed countries is not obese. It's easy to look that up. This proves that we don't live in an environment that makes everyone obese.
Please don't cross into personal attack, regardless of how provocative another comment is or you feel it is. It only makes things worse, and we're trying for something different here.