The reign of Japan’s king of speed eating, the munch master Takeru “Tsunami” Kobayashi, is all but over, his all-devouring dominance undone by an arthritic jaw.

He described the affliction as an “occupational hazard” that has all but crushed his hopes of defending his title at the Nathan’s Famous July Fourth International Hot Dog Eating Contest, in New York next week. The diminutive Mr Kobayashi, 29, first outgobbled his most voracious American rivals at the speed and volume event seven years ago.

Since then, despite a relatively svelte frame and weight of less than 75kg (11st 11lb), his stomach-distending feats have never failed to astonish audiences and fellow competitors in the gluttonous cabal of United Food Fighters.

Record after record has fallen to Mr Kobayashi: disciplines including hotdog, bratwurst and other “all-American” speed and volume eating. He recently emphasised his dominance by polishing off 97 hamburgers (complete with buns) in just eight minutes.

In Asia, he has beaten all-comers in competitions involving improbably huge volumes of vegetarian dumplings and fried calf brains.

Mr Kobayashi’s hotdog eating prowess is attributed both to his natural ability to push the stomach below the ribcage to accommodate more food and to his famous “solomon” method of splitting a hotdog and then dipping the bun in water to make it more edible.

Yet in an emotional entry on his blog, Mr Kobayashi revealed that his rigorous training regime, which involves stretching his stomach with large quantities of cabbage and water, had left his mouth all but paralysed.

He will still enter next week’s competition, however, viewing the physical pain of eating as “meaningless” compared with his grief at losing his mother this year. “My jaw has given up the fight,” he wrote, adding that the arthritis was so bad that he could only open his mouth wide enough to form “a gap the size of a fingertip”.

In a revelation that will likely stun his rivals, Mr Kobayashi said that he has been battling against arthritis for more than two years, setting new records despite feeling “like my jaw was dislocating”.

He goes on to berate himself for not accepting the inevitable sooner. “I feel so ashamed that I didn’t hear the alarm bells ringing in my own body,” he writes, “but with the aim of winning the title and setting a new record in my head, I couldn’t stop my training regime so close to the competition.”

If he manages to win next week’s showdown, Mr Kobayashi said that he hoped the victory would make his mother proud.

Keen observers of the 12-minute-long Fourth of July hotdog eating competition are wondering whether even a fully fit Mr Kobayashi would be up to the challenge posed by Joey Chestnut, a Californian who, in a separate competition, has already beaten the Japanese champion’s record of 53.75 hotdogs in 12 minutes.

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