smoothies?
full fat everything dairy

You do have my symapthy and empathy. 2yo are hard. Mine went for a full fortnight and would only eat frozen peas once. I kid you not.
What helps here...ummm
how good is his comprehension/language? Choices work well here, between a couple of options (we've always done BLS so he's used to this and they surprisingly usually pick what they need) or where do you want to eat (amazing what a change of scenery will do, be it a picnic somewhere random, at a different table, outside etc)
cut up stuff really small - DS will eat tiny sandwiches, but not a whole one.
give them less than you want them to eat. DH was horrified when I gave DS a tiny amount of dinner last night, but ate his words when he came back for more (eating dinner is something new here....for the longest time he didn't eat any)
sometimes a multi vitamin will help boost their appetite.

GL.