Translation:Steak is, according to her not real food, because she is vegetarian.
Firstly, the actual nature of food is irrelevant to what she believes. Secondly, there is an argument to be made about ethics determining whether or not something should be considered food. I mean, you can digest human flesh, but you wouldn't consider me food, would you? Maybe you don't see animals as having moral value, but she does, so to her the animal is not really food.