When he was a bit younger than 2, but with a similar amount of upheaval my DS went on a hunger strike. He ate nothing but a few frozen peas at a time for a full fortnight. It took all my fortitude, but what helped in the end was ignoring the strike and carrying on as normal.
Does he speak well your little guy? I was able to ask mine what he wanted (he didn't have many language skills but could communicate reasonably effectively). He only got to choose from food I wanted him to eat, but sometimes that control for them helps. Gradually he took more of what was on offer.