This same thing happened to my daughter when she was turning 2. She had previously LOVED the Gerber stews, and then one day decided they were yucky. Then she would refuse to eat anything besides Mac&Cheese, Grilled Cheese, Pizza or Chicken Nuggets. I think she liked the Chicken Nuggets because we got the Perdue Fresh Nuggets with Cheese in them (notice her love of Cheese!).
We started putting portions of our dinners on her plate just to see if she would try them. Then we would slightly ignore her during dinner, and every once in a while she would take a taste of what we were eating.
Now she loves to eat EVERYTHING. Spaghetti and Meatballs, Hotdogs, Grilled Chicken, Ribs, EVERYTHING. But we don't push her. She is 2 1/2, and we tell her that she has to eat one bite of everything, even if she doesn't like it. She is usually pretty good about following that rule.
Good Luck! You may just have to wait it out!
D.