Where did my good eater go?

Since Noah began eating, he has always been an excellent eater. I think one time he didn't like the stage 3 foods (pretty sure it was chicken noodle) but he liked it the next time. I just think it was the change in texture. Well now whenever I give him anything new, he loves it the first 5-10 bites then he spits it all out! For example, on Saturday I made this Gerber graduates side that was cheddar mashed potatoes and broccoli (which stunk SO bad when I heated it up, but Clint said it was pretty yummy). The first few bites, he loved it! Then all of a sudden, he started sticking his tongue out and like gagging. However, he would still accept the spoon of food when I gave it to him. It's so odd. I hope this isn't the beginning of boycotting food! He was such an easy baby because he liked everything...hope those days aren't long gone!