How did you overcome 'eating your feelings'?

I will think I've beaten it, succeeded, and then I'll be stressed out one day coming home and think "screw it" and stop at a convenience store and then eat a whole big bag of chips in one sitting or some other variant of that.

I know that changing behaviour isn't always linear, and slip ups happen. But I haven't seen anything about how to beat them, only that you should. And I know I should. I don't want to eat that stuff, I don't want to feel sick and guilty from it. But there's a part of me that still wants to, and it's a destructive part, and I'd very much like to overcome this.