Question Thick neck, goiter?

My son is grown and out of the house, and he eats alot of pizza and fast foods with his friends. They are young men but they look so bloated and puffy. He started looking that way to. where his neck and his head are hardly distinguishable anymore. He does not have a whole lot of body fat, it looks like a healthy amount. Is the thick neck a sign of goiter? He said he will take an Iodoral pill every day so I hope that helps.