Adopted children and food obsession?

I LOVE these suggestions. My son has food issues and I suspect he will have them for life, on some level. He came to us at 11 months old. His foster mom said he he had issues at 3 months old and would rage for more bottle/food even though it would make him vomit. Her take on it was to restrict him and put him on a "diet" because he was "too fat" he gained only 2 lbs from 3 months to 11 months. When he would see other children with bottles from 8-12 months he would rage and scream for their bottle. He was not very big when we got him but could out eat my 8 year old in pancakes. For a very long time he would scream and throw fits for a bottle even when he was weaned. It was weird because often at night time (we gave him one bottle at night and nap time for attachment) he wouldn't even finish the bottle. I think he was attached to the "food" like it as his caregiver. I am not sure what the answer is but for him he almost has to have free access to food or he goes nuts-to this day if I try to restrict him we backslide. When he is allowed all he wants of healthy food he seems to moderate himself better. I can't have anything sugary/junk food in the house or he will find it and rage if he can't have it. I get him a child size chocolate shake from McDonalds (therapist suggested it) almost every day, but that's our "junk food". Free access suggestion was given to me by somebody on the board. However, if he didn't restrict himself on healthy food, I would be very worried. At first he did eat until he would vomit so I did have to be careful not to let him have too much until he was around 18 months old and he started to regulate better-even then tried very hard to let him have healthy choices even if it meant he overate-. I wonder why so many adopted children have this problem? Oh and he doesn't have weight problem he does have sensory issues.