If (big if) she's capable, she's not capable right now. You can see in the contortionist act she does to try and twist things to convince herself that even though her current approaches have failed again and again and again, they will work this time.
The hard truth she doesn't want to face is that if she wants to be successful there are things she will have to control herself with. The number of times she goes out to eat, the types of foods she consumes would be examples of this. Actually, at her weight she wouldn't have to do much to see results, but the barest hint of restriction, or even not being able to outright binge whenever she wants, sends her into a mental tailspin that has her binging even harder. She wants to have her cake and be able to eat 73 of them too, but then the shame spiral attached to that has her running back to unrealistic goals. Until she's willing to take a deeper look at herself and her limitations in terms of how she's capable of dealing or not dealing with food, she genuinely can't change. She'll keep implementing systems that deep and not so deep down she knows she can cheat. The brain can be a tricky thing at the best of time, and when you're feeling kind of trapped in your relationship with food this way it's really easy to go from 'I'll eat X calories of healthy things' to 'Anything so long as it's X calories' to 'anything' to 'everything'.
I think AL is genuinely scared to lose food in the way she currently has it, and whatever it's doing for her. More so than she's scared to be the weight she is (even though she also hates that). I think that's the reason she wouldn't do weight loss surgery even if the option was completely cleared of obstacles.
I think with professional intervention and support, and a lot of work, she potentially could change. But I think it would be a harder road than she'd be willing to walk.
If only someone had thought to tell her to see a therapist to help her with this...
