I wonder what changed in between? Maybe our food and our relation to it? Who knows right?
You believe incorrectly.
> They're fat because they have ignored that advice for a long time.
Ah yes, the medical equivalent of "works on my machine".
You've now shifted from "how effective is this treatment" to "whose fault is it when the treatment doesn't work".
You will be able to help the fatties when you shift back into asking the question that matters.
But you are right with the fact that at the end, it mostly doesn't work. But those who stick with regime, it works 100% and positive changes in life, quality, happiness etc are massive.
The real solution - treat underlying mental issues. They are always there with obese people, they are massive (no pun intended), and they manifest as obesity, among plethora of other mental issues.