I'm not an expert on this issue, but it seems that your child could be refusing to eat for several reasons. He may have a sore stomach or he may just prefer certain foods that you yourself don't. My advice is just to be patient with him and allow him to make his own food choices. Try giving him a selection of different foods and see what he likes. Maybe he'll prefer vegetables over meat, or fruit over vegetables. Some children, I think, can be inherently vegetarian from birth, and it's when their carnivorous parents try to introduce meat to them that they make a face.

Alternatively, he could be too excited to eat. Often the sense of hunger goes away when you're excited about something (my 1 year old nephew is often excited when he visits and his mother finds he has a refusal to eat just because she wants to feed him right after he comes through the door, when a better approach might be to let him get used to his new surroundings first)