Two groups of boys 7-10 years old who are very short and below average in weight but otherwise healthy will be studied. One group will be observed initially for 6 months and then receive GH injections every day for the subsequent 12 months. Another group of boys will get a high-calorie drink every day for 6 months, and then receive GH injections plus the supplement every day for the next 12 months. We will compare how well boys grow in height, weight and the changes in body composition. We will compare diet and energy usage using the doubly labeled water technique. A battery of hormonal and nutritional tests will be performed, as well as body composition assessment.