My baby is going to be 1 year old a week from now. It's been a month that he doesn't like to eat solid food. These few days he does not eat any solid food at all. We've been tried giving him cereal, rice soup, oatmeal, pastas (ABC noodles, short thin rice noodles, etc.), baby food, and bread. But he always says no (by moving his head) even before trying the food. He used to like bread, but he's not even interested in it now.
Also, it's not easy to feed him milk either, but at least he'll drink some.
I don't know why his appetite dropped so much. He already has 3 teeth (a very big one on the top), so I'm not quite sure if it's due to teething. Also, it doesn't look like he's sick.
My 1 year old daughter also had the same problem before. She didnt want to eat solid food and drink milk too, may be just tried 1 or 2 spoon. In my opinion, I think your son may be teething if he doesnt look like he is sick. Nothing you can do but keep trying to feed him different kind of foods. I am sure it only a stage, be patient and wait. Thats what I did.