I always thought it was beer belly too, until it happened to my own husband. He has never had a beer in his life, and he drinks wine very sparingly. His is from sitting at a desk all day and all night. He is on his computer nearly every waking moment of the day, and even eats at his desk.
Over the last few years, he has cut back on the amount of food he eats, and he tries to force himself to go on the treadmill at least three times a week, but it doesn’t help. This week, with the nice weather, he is walking during his lunch hour, and parks a half a mile from the office, so walks a full mile to and from the car.