Hi , I have read up on your email that you have sent , and it could be that your son has hyperthyroidism - over production of thyroid hormone (please dont quote me on it , I am not a doctor!!) this regulates many aspects of our metabolism eventually affecting how many calories we burn , how warm we feel , and how much we weigh. Common symptons are ; palpitations, heat intolerance , nervousness , insomnia , breathlessness, increased bowel movements , fatigue, fast heart rate, trembling hands, weight loss , muscle weakness , warm moist skin , hair loss, staring gaze, signs & symptons have different medical meaning , symptons are problems that a patient notices or feels and signs are those that a physician can objectively detect or measure. Please let me know how he gets on , I am sure it isnt this. I thought I would try and help in some way , as I know how parents worry.