M.T.
I would ask your son's Dr. what he/she thinks before you make a change like that. We didn't use it with our first two children and I know that we wont use it for the future children. I don't see it as anything more than a way for the formula makers to make more money. My three year old goes through phases, sometimes she eats all day long and sometimes it's painful to get her to take two bites. She is perfectly healthy and she's in the middle (I hope) of one of her I don't want to eat phases.