there is another forum on medhelp that deals with children's behavior. Fights over the control of food are not uncommon, but your daughter has taken it to the extreme and is risking her health...please contact the other forum, or a specialist in child behavior, like a psychologist or psychiatrist.
P.S. In addition, she has been quite poorly in health ever since she started diminishing the already small amount of food she used to eat. Comes down with fevers or flus quite frequently these days - about two to three times a month if she goes to school, and about once or twice a month during vacations. She also seems to have lesser energy than kids her age, she hates any kind of exercise, dancing, walking or activity, preferring to just sit or stay put in one spot all day. I'm just a bit concerned, but maybe I'm overeacting?