Our parents cat recognize the word "fat". I already knew that he knows at least "food", his name and "out". But apparently he also know that if "fat" and "food" is in same sentence, it is less likely he will get food from that person. One time I put some food to my own cat and our parents cat had his food already. He still tried to eat my cats food and I just pointed him with finger and said: "You are fat." The cat backed up two steps and looked sad while my cat ate his own food.