i watched some special on sumo wrestlers a couple years ago. they eat insane amount of calories. granted, it's mostly "clean food", but 10,000 calories of sushi a day still makes them fat as shit.
they do almost no resistance training at all, and if they do, it's shit like lifting a rock or something. they get most of their workouts from sparring, if you can call bumping tits sparring.
with all that said, they're still more popular than bb'ing will ever be.