To offer a more precise diagnosis you would need to offer much more information including an accurate tongue diagnosis and pulse diagnosis. Generally, however, anorexia would likely cause Spleen and/or Kidney Yang Deficiency. Given her age Kidney Yang Deficiency would likely be a large part of her imbalance.
If you read the section on Kidney Yang Deficiency (here) there are some recommended treatment points. Moxibustion could also be helpful on points such as KD 3, ST 36, CV 6, etc.
Anorexia, however, is ultimately a brain chemistry issue so a full treatment also requires working on that aspect as well - many times this is a KD Yin Deficiency or a HT Yin Deficiency.
From the Tam Healing System, I use tuina and/or acupuncture on such points as UB 13 and the C2 area to effect the frontal lobe.