The 41-year-old competitive eater has no problem consuming 62 slices of pizza in 12 minutes, or 337 chicken wings in a half hour. But seeing himself onscreen in the latest ESPN "30 for 30" documentary series, is a little harder to swallow.
In a recent interview with The Associated Press, Kobayashi says that while he was "honored" to be a part of the documentary "The Good, The Bad, The Hungry," he was also a little perplexed.
"I don't know exactly what's happening," Kobayashi said.
Then, through his translator, Kobayashi was able to go into more detail about why he was so self-conscious.
"I'm so embarrassed when I see myself in the film that I can't even watch it," he said.
Premiering Tuesday, the documentary comes two days before the annual Nathan's Famous International Hot Dog Eating Contest that brought Kobayashi to prominence in the competitive eating arena.
The documentary shows the rivalry between the six-time champion and the current 11-time champion Joey Chestnut, who dethroned Kobayashi in 2007.
Holding 15 world records, the 128-pound Kobayashi explains his preparation for eating.
"I have to put something inside the stomach to make it expand, but it doesn't necessarily have to be food. I train with water. So, I'm not training for long periods of time by hauling food. I'm training with water expanding my stomach," Kobayashi said.
After a competition, it takes him about three days to recover.
"I feel so exhausted and so out of breath," Kobayahi said referring to his stomach being over-extended, and the toll it takes on him.
"When my stomach becomes very full with that amount of food inside, the organs in my body begin to shift places. So, for example, my lungs get shifted up, and they can't expand. They have no room to expand. So, when I breathe, I become very short of breath. That's one of the main things that happens right after eating," he said.
Another thing is getting sick. But he says it's not something that happens as much as people think. "If I'm going to be sick, it happens right after."
While he's eaten almost everything in competition from bunless hotdogs and rice balls to lobster rolls, one of the oddest is cow brains. He ate 57 of them, a total of 17.7 pounds. And did it in 15 minutes.
But there's one he loves to eat above all.
"I savor hot dogs," he said.