How Does He Do It?

Here is Big Country Nelson out pointing Frank Mir in a grappling match:

http://www.youtube.com/watch?v=2dj5xMeXybs

Here is a recent pic:

He was pretty slim in comparison during the Mir match. They guy still has mad cardio though. How does he do that?

http://mmajunkie.com/news/20216/ask-the-fight-doc-is-ufc-heavyweight-roy...

To train at the rate that he trains and to still keep the gut is a feat in itself. He must compete in eating contests between fights or something.