Hard to comment without knowing more,
Is she still feeding herself, could it be she needs help with eating?
My husband lost interest in food when it became difficult for him to use a knife and fork. Changing him to finger food, helped greatly.
When he was no longer able to manage this and needed to be fed, his appetite increased.
I don't think it is possible to detect what is normal with this disease, as everyone is individual.
Is she old? sometimes age determines appetite.
I'm trying to help here, but don't seem to be doing a great job of it.
If you're really worried about how little she is eating, maybe check in with her GP.
Good luck Bastan x