Getting fat is a bit of a trap, both hormonally & physically. Can you imagine trying to move with an extra 100lb skin attached to you? Once you stop moving you're dead in your mobility scooter, it's only a matter of time.
It's much easier to avoid getting fat than it is to get unfat.
Some eat the most horrendous shit - they've given up. Others eat what they've been told to eat (salads, fibre & lean meat) - they don't know how to eat.
It's pretty simple when you know, but that knowledge goes against everything the health authority says. It's a fiat condition.