overweight child with Hashimoto's

My 9 year old daughter has gained significant weight prior to diagnosing Hashimoto's. The disease is now under control but she is still overweight. She is active but eats compulsively. She eats similar quantities to her peers but needs to lose approx. 10 lbs to be at her ideal weight. I don't want her to end up with an eating disorder though at this critical age. The rest of our family is not as overweight as she is. Her siblings are skinny and her mother (me) is about 10 lbs. over "ideal" weight. Her dad is slim. Any suggestions?