If he's on meds for ADHD, is he eating consistantly? I can always tell if my nephew has had his medicine by whether he's eating or not. He is 9 years old and very small for his age. I know the meds are a huge appetite supressant and it's hard to force them to eat when they're in their system. I personally am taking Adderall, not for ADD or ADHD, rather I take it to keep me awake. I have a sleep disorder and this med has a different affect on me. I've lost between 25-30lbs since I started it, because I just don't feel like eating (which isn't a bad thing in my case). When I do have a desire to actually eat, I'll skip it until after lunch or just not take it at all that day....then I end up eating like a horse. My nephews doctor takes him off the meds in the summer so his growth can catch up, because it also stunts his growth. Hopefully some day they will come up with a better alternative. Have you tried a gluten free diet? I've heard good results with that as well for ADHD. Good luck, and happy birthday!!