What Is The Treatment For Loss Of Appetite And Headache?

hi i am very concerned about my daughter she is 18 and for the last few months she will not eat anything containg much sugar she has suffered with headaches and thought this was the cause ,she is on amitriptyline tablets but also takes nurofen.she has one slice of toast for breakfast with buttern wont eat cereal cause of sugar .takes crackers for lunch but eats about 3 packs of crisps a day.we always have a healthy dinner at night with plenty of veg but now she wont eat carrots . what ever she eats now seems to go straight through her could this be the medication or so much fat from the crisps