A crowd of 25,000 watched Kobayashi, 27, take his sixth annual July 4 hotdog eating title at Coney Island in Brooklyn, New York.

Most cheered for his arch rival Joey Chestnut from San Jose, California, whose final tally was 52 hotdogs.

"I'm not happy with the result, I'm going to be back," Kobayashi said through a translator. "I can do more but I'm not sure I want to tell you (how many)," he said, adding that hotdogs are not even his favourite food and he prefers tofu.

Standing just five foot six (168 cm) and weighing 170 pounds (77 kg) before the contest, Kobayashi proved size isn't everything in competitive eating.

Under pressure from the 22-year-old Chestnut who stands six foot one (185 cm) and 225 pounds (102 kg), Kobayashi kept his cool throughout the contest, maintaining a steady pace.

Chestnut, winner of the world deep fried asparagus eating championship, strained and turned red as he shoved fistfuls of hotdog into his mouth.

After his win Kobayashi bit into another hotdog to celebrate as he posed for photographers.

He was one of 20 competitors in the contest at the Nathan's beachfront hotdog stand. Standing in front of a long table on a stage, the eaters dipped the dogs in soft-drinks to help them go down, monitored closely by judges who kept count.

The contest drew competitors from the United States, Sweden, the Czech Republic and Japan. The only woman in the running was Sonya "The Black Widow" Thomas, of Alexandria, Virginia, a petite 38-year-old of 100 pounds who earned her nickname by beating a string of men at eating events.

"I'm not satisfied, I could be better," she said after taking third place with 37 hotdogs.

Competitive eating is a popular sport in America, particularly at holidays, with contests for everything from chicken wings to "turducken," turkey stuffed with duck stuffed with chicken.

The US Centres for Disease Control and Prevention has found that 65 percent of US adults aged 20 or older are either overweight or obese and 30 percent of adults are obese.