In the episode where Timmy wishes he was invisible, in the science lab when AJ and Chester are about to disect the frog AJ says that he a vegetarian. But in other episodes he is eating meat. For example in the episode when Timmy has a sleep over gone bad and then has to poof between Chester's house and AJ's house AJ is eating seafood, and in the episode where Timmy wishes there ws only junk food AJ's dad has eaten the food on AJ's plate, and the empty plate has bones on it, so AJ would normally eat food with bones in it, and vegetarians don't eat eat anything with bones.