Hi supportive mom,
Fortunately my girls dont have this disease, but this is my worst nightmare.
When I got diagnosed, I found it difficult at first to incorporate food for the whole family, because I was sick. I wanted to make sure that they ate normally to avoid missing out on nutrients. So basically, until things settled down....maybe a couple of months, I ate food separately to what they ate.
I hope this helps in a small way. Children, can be difficult when it comes to food at the best of times, but i think you will just have to be firm, but nice and explain that this wont last forever...your daughter will be happy once it all settles down and she can enjoy a little bit of normal, but she will need to be more vigilant than all her friends.
Good luck and let me know how it all goes.