On r/relationships a couple of years ago a woman came to ask for help because she'd had a meltdown and accused her fiancé of trying to starve her to death. She was panicked he was about to break up with her due to her verbally violent outburst but that fear was overshadowed a bit by her realization that she is fat because she drastically overeats.
Girl is fat, from a fat family, insists her fatness is genetic. Meets thin, fit dude who does not mind her weight, they do couple stuff like go out to movies, eat dinner at restaurants, get snacks at ball games. They get engaged, move in together and she's is initially thrilled that he wants to cook the meals. Most of the meals consist of vegetable-heavy stir fries with some form of lean protein. No rice. No lo mein but plenty of servings of stir fry. Generally no dessert.
After two weeks she lost it and demanded to know why he was starving her. Puzzled, he asked what she meant, that this was always how he ate but she responded that oh no, he always had appetizers, Mac and cheese, burgers, brownies and other calorie heavy meals. He told her that the treats on the weekends were not daily eating, that no once could eat like that every day and not be unhealthy. She ate like that every day and so did her family and as he left to walk around to cool off, she realized that her family probably wasn't fat due to genes. She really did believe all her thin peers ate pizza and huge pasta meals and burgers and fries every day of the week and stayed slim because she never knew what they ate at home and how much they exercise. She expected his stir fry to be like the stuff she got at PF Changs, where she treated those family sized platters as her own plate. She really did think everyone ate cheese cake or ice cream daily for dessert.
AL has this problem. The wretched excess of food served at American chain restaurants has skewed the perception of normal food servings and not knowing how others truly eat when they are not with you makes you think you eat similarly. The best case scenario for Amber to lose weight is to stop dining out or at fast foods so she can reset what he brain considers healthy portions. That is about as likely as a brick of gold falling out of my ass.