A Toddler's Eating Habits

When Nicholas was just beginning to eat regular table food, I thought he was going to be the best eater ever! He would have vegetables, meat, fruit, and usually some type of bread. He would gobble up everything on his plate and be ready for more. Now that we have entered what seems to be the early terrible twos, nothing is the same. For days in a row the only thing he will eat is a hot dog. Then all of a sudden the hot dog is tossed on the floor with the toys as if to say "What is this! Why on earth would you make this for me?" He used to love every vegetable including peas. Now the only one we can get him to go near is corn on the cob! One would think that he would also eat the same corn we do, but that is not the case. Only corn on the cob will do! He spits out chicken, turkey, steak, hamburg yet today he ate a whole piece of "ham" off of an Egg McMuffin sandwich! Does this make any sense? How can you eat the so called ham from McDonald's of all places but not any other kind of meat??