I know some serious cases where there were non-habitual problems but... "healthy habits" is nothing to laugh about. People literally are what their habits are.

I know some serious cases where there were non-habitual problems but... "healthy habits" is nothing to laugh about. People literally are what their habits are. All of our behaviour is habits, and changing behaviour takes time and effort. The good news is that it is not impossible, and it really is possible to change bit by bit for most people suffering from obesity. I don't think somebody who walks 10k+ a day, maybe goes to gym a couple of time a week, limits calorie intake to a comfortable and reasonable 2000 kcal per day, would suddenly bounce back to 130kg!