I "beat" obesity in the last year. My BMI was low 30s and it's now low 20s. Knock on wood, after some time I don't seem to be regaining it like a lot of people do (as suggested by my sibling post). Without getting into too many personal details, the biggest thing to cause that was a radical re-shift of my work habits. A vast majority of people do not have the luxury of chosing when and how they work. I do not fault them for not replicating what I did. I struggled with it myself for a long time, before my recent success, until I was able to make these latest changes.
In general I think things which lead to judging other people for their circumstances is a bad idea. There are probably people who could will it away. Is it their fault that they don't? Honestly, probably not usually.