Turtle started out as a very cautious eater. While Tadpole followed her usual "why the hell not?!" approach to eating, Turtle would make a face as if to say "what IS this crap you're putting in my mouth?"
Then he decided he loved food, and he munched down everything we gave him. There was nothing he didn't like, and it was fun to make food for him and see if he liked it, which he usually did (after his first few suspicious bites).
Then he regressed. He started making much worse faces and gagging (more like "If you continue to feed me this disgusting stuff, I will probably die"). He started arching his back and throwing his head back and whining and crying and being just plain miserable. He started refusing to eat.
We discovered that he wouldn't do that with sweet foods - fruit, fruit-flavored yogurt, and sweet potatoes. So I started making sweet potatoes and gradually mixing other foods back in. When he wouldn't eat, I'd get desperate and open a baby food jar of fruit. He started recognizing the "pop!" of the jar and would get excited.
Last night, he refused to eat the sweet potato, carrot, and leek puree that I made. In a stroke of genius (which may prove to not be so genius in the end), I put it in a baby food jar. He ate it all up!
Which just goes to show you ... something. I'm not sure what. Babies are clever and stubborn creatures, and you have to be even more clever to outsmart them sometimes.