Kim Jong Kook and Yoo Jae Suk talked about how much the 'Nation's MC' has changed over the years.

On a recent episode of 'Gym Jong Kook', Yoo Jae Suk shared, "When I was on the show 'X-Man', I ate at dawn after filming, and Kim Jong Kook was only packing egg whites for his meal at the time. He told me to exercise, and I said I didn't want to. He then told me that I would die. It was an extreme thing to say."

He continued, "I was in my thirties at the time too, and at a certain point, my stamina during filming wasn't so good. That's when I started to go to a gym, and now I go all the time." Kim Jong Kook added, "The Yoo Jae Suk from back then and the one now are different."

Yoo Jae Suk then said, "That was when I smoked cigarettes, and I didn't even breathe right. Now, I have kids and I'm married, so I quit smoking. I thought it would be difficult, but it was easy to quit." 

Watch the episode of 'Gym Jong Kook' above, and make sure to turn on the English captions.