6 year old daughter being labeled "problem"

I'm new to the sugar sensitivity community. I've long searched for research on food allergies that affect mood for myself without much success. My current crisis is for my 6 year old daughter who has been labeled a "behavioral problem" by her teachers her whole life. I KNOW even if I can't explain why it's happening that food is playing a big part in her behavior. I bought and loved Little Sugar Addicts but still don't have a handle yet on her behavior. I'm missing something. Any carbs even complex affects her. Even 10 grams of sugar in milk affect her drastically. I feel so powerless to help. What am I missing?