I've been in this situation, and mine, got worse. My advice is this: make him sit with you at the table, and offer a few choices from what you're having. If he chooses not to eat, don't make a scene about it, but don't feed him later when he's hungry either. Most children will come out of it on their own as long as you're firm on the rule that if they don't eat at mealtime, they don't eat until the next one.
Here's where it went wrong for me. I'm living with relatives, who come from a more "old school" approach to parenting. They felt I was being cruel, and behind my back would give him whatever he wanted later in the night. Now he's 4, And can and will choose not to eat a single thing for as long as 36 hours (which is as long as I've ever let it go on), unless it's what he wants to eat. His doctor advised me, in this situation, to just give him a vitamin everyday and make sure he eats something, keep offering good foods etc... but if you can avoid this, please god do. It's frustrating beyond belief, and now that it's too late, even my relatives agree it was a mistake to give in and feed him later in the evening.