Caveat: I'm not someone with a lifelong struggle with weight, so I'm not saying what happened with me applies across the board.
I was about 20 lbs. heavier than what is usual for me. I decided I wanted to lose it. I decided to utilize mindfulness in the situations where I would normally automatically indulge an impulse to snack (this was the biggest source of the weight gain).
It actually worked. I would notice the impulse, pause, know that I didn't have to blindly follow it, and that it would pass w/o indulging. (Ordinarily, it seems like the only way to relieve the desire is to gratify it.)
Very handy that the practice actually worked!
"Why is it, Master Kaccana, that ascetics fight with ascetics?"
"It is, brahmin, because of attachment to views, adherence to views, fixation on views, addiction to views, obsession with views, holding firmly to views that ascetics fight with ascetics" (AN 2: iv, 6, abridged).
Kindly eyes, not verbal daggers.