Could well be a definition thing, looked at an old picture of when in the Army the other week and the one guy we called fat, didn't look it at all. Where as today, people have to be very fat or indeed obese for them to be termed fat, it also depends on where your wife teaches.
You can't call people fat anymore, its not politcally correct. They may have suffered some form of abuse during childhood, they may come from poor backgrounds that can only afford the attractively wrapped food in supermarkets,they may have fatty liver, or been bullied at school, or an overactive...