Why is everyone in K-1 so huge?

I've seen a few K-1's and had a look at the k-1 photo thread and I've hardly ever seen any lightweight fighters. Why? It seems like most of the guys are well above 200lbs and have been hitting the weights quite a bit. Is all the muscle really necessary for a k-1 fight?

The Japanese like larger than life fighter's who have a character.

Maybe it is because they have no weight divisions.

That would make sense to me.

The 1 in K1 means one weightclass although now they have added another class too.