Even if he's not dramatically overweight, I'd definately wager that this guy is probably in very poor health.
Not necessarily. There are always exceptions to every rule. It's why some people can eat fatty foods, never exercise and smoke all their lives and live to be very old (I'd assume their
quality of life is not great) and why others, for example someone like Linda McCartney, who was a vegetarian and didn't smoke, died of breast cancer in her 40s.
Who knows what else this guy eats when he's not eating a big mac. He may get a decent amount of activity and he's allowing himself to indulge in something that he loves (unlike the people who would eat fast food and beat themselves up over it later. Maybe just women do that... I don't know).