She has to learn that YOU are in charge
of the food, not her. She gets fed when YOU decide, not her. I do think this might help her to trust. You could start by getting her on her own, and saying "sit, wait, stay" only going for the treat when you tell her she can do. Graduating to being able to do the same when her dinner is put down for her. You might have to leash her to do this, while she learns a little discipline, trust and patience.