we tried this with our niece and beleive it by evening she was so hungry that we were surprised

Hi I've read the responses and as a mother whose raised 3 children, plus as a qualified Homeopath, Naturopath and Herbalist I have a few ideas for you to try.  IF you have a practitioner Homeopath nearby and one who does Flower Essences then I'd go and get some.  Bach flower essences are excellent and so are many of the FES ones.  I would suggest chicory (as its a means of getting attention, the non eating), Chestnut bud, (to change the habit), Mimulus (as he/she may have inner fears) Walnut (for going through changes in their life, and sensitivity to outside influences) - often a practitioner will make these up and mail the to you (I know I do) for a little cost.   Give these clear liquid drops straight onto their tongue, 4 drops four times a day, to work on the underlying emotional reasons for not eating.   I know you give milk, but how about getting a good protein powder and add that to it...OR make up a protein shake, 1 egg, 1 cup of milk, 2 teaspoons of honey (more nutrients than sugar), some strawberries (or else some cocoa powder for choc flavour).   Also I woud find a good liquid multi vitamin (with herbs and iron in it) and get a teaspoon or two in per day.   BUT the flower essences will be the most important as children are great at manipulating us emotionally.  Especially if other things happening in their lives, like a new sibling, or change of school, or fears of being left out in some way.  So treat the CAUSE. Also Chammomile 30c would be an excellent homeopathic to give to.  Hope this helps.