Inclusion Criteria:  GH treatment for at least 24 months due to idiopathic short stature (ISS) Age 5-10 years inclusive. Tanner stage 1 (gonadarche). BMI <85 percentile for age and gender.  Exclusion Criteria:  SGA/ IUGR Diagnosis of GH deficiency Any known morbidity: chronic disease dysmorphic syndromes, bone diseases, organic brain diseases, neurological disease, past or current malignancy, chronic cardial, renal or pulmonary problems, metabolic disorders. Any known gastrointestinal problem including absorption problems. Any chronic treatment with medication that might affect appetite, weight or growth (for example SSRI's, steroids). Any eating disorders and/or psychiatric disorder Milk or other food allergies