What helped me begin to unravel my diet brainwashing was realizing that my own judgments were the problem. I spent a lot of time trying to figure out which judgments were right. I had bunches of them - Thin people are healthy. Fat people are unhealthy. Anybody smaller than me has a worse eating disorder. Dieting is healthy and virtuous. Not dieting means giving up and losing control.
When you lay it all out there, it was the act of telling myself these stories and believing them was causing pain and difficulties. How refreshing to realize that none of it is true! There are always exceptions, unhealthy thin people, world class athletes with obese BMIs, lives wrecked by dieting, freedom and good health found by giving it up. Up is down, down is up, dogs and cats living together. LOL
Once I got clear on that, I could let go of my old blanket statements and screwy belief systems, not worry about those other people I was so fond of analyzing, and just think about what I wanted for lunch. It simplified everything tremendously.