In reply to Quornflakes ... who by her own admission "has no experience of ED's" but is commenting on this thread about a child who is currently suffering, and requiring specialist treatment, for ED's ...
Community/outpatient ED services may support support highly considered and balanced vegan diets in patients that are at a lesser medical risk, BUT as I stated all inpatient units (that I know of/have attended) do not allow vegan diets.
This is due to the need to refeed patients who often critically/severely ill on admission (with critical electrolyte, potassium and blood sugar abnormalties and hypo-metabolism amongst multiple other medical issues (caused by severe anorexia/bumimia/occasionally chronic binge-eating).
These patients need to be refed quickly and medically safely to prevent fatality (in the case of anorexia/chronic bulimia). Due to the body's inability to digest many foodstuffs when the stomach has severely shrunken/digestion system is entering 'shutdown' ... and therefore the need to refed quickly on foodstuffs that the body is able to easily digest when in a dangerously ill state is a priority ... inpatient units will refed only following a vegetarian, pescetarian or meat-eating diet (not a vegan diet), in my experience.
It was explained to patients that it is not about prejudice against vegan diets, it is about acting in a medically-safe manner to refed them quickly. And yes, in the case of anorexia, the patients are forced to eat many, many things they don't want to ... against their wishes ... in order to save their lives! ED inpatient units do a great job, so I just want to clarify why they take this stance.
I realise (thankfully) the OP's DD is not in need of this level of treatment currently, but feel the OP is asking out of concern due to her DD's past/current history of ED's ... not because of a need to be educated about the pro's/con's of a vegan diet. I will 'bow out' now, but hope the OP finds some of the response's on this thread will give her 'pause for thought' ...