In Tokyo, the fast food of choice is a towering concoction of four hamburger patties, with all the trimmings, crammed into a single bun, while children happily line up around the block for a calorie-laden doughnut.
But while the queues outside the Krispy Kreme doughnuts in the Shinjuku area of the capital, which opened recently, point to an extraordinary Japanese success story for the fast-food industry, they also symbolize a health disaster in the making for consumers.
Up to a fifth of Japanese children aged between five and 12 who are overweight suffer, or are at risk of developing, metabolic syndrome, a range of symptoms including high cholesterol and large waistlines, according to a study released last week. Left untreated, it can lead to serious illnesses such as strokes and heart disease.
Nationwide, the condition afflicts an estimated 23 million Japanese, the health ministry warns.
Though middle-aged "salarymen" are at greatest risk, children as young as nine are now suffering from type-2 diabetes, a phenomenon unheard of in Japan only a few years ago. Experts say the looming health crisis is being fomented by a surge in demand for highly calorific food sold by the top US food chains.
Experts blame adults for setting a poor example.
"Ultimately it is up to parents to take greater responsibility for what their children eat," said Fumi Hayashi, a researcher at the National Institute of Health and Nutrition. "The problem is that they are just as guilty of bad habits rather than eating a balanced diet."
Now diseases associated with obesity will strike Japan faster, and with greater ferocity, than anything seen in the West.
"When you have rapid trans-formations in lifestyles, that's when you see the worst health outcomes," Asia-Pacific regional coordinator for the International Obesity Task Force Tim Gill said.
The rapid changes taking place in the Japanese diet, combined with a greater susceptibility to metabolic illness, will lead to dramatic rises in strokes, diabetes and hypertension, he said.
"The potential is there for a disaster," he warned.
In the absence of government intervention -- limiting TV advertising aimed at children, or banning special promotions -- the fast-food industry is enjoying unprecedented success in Japan.
Held responsible for contributing to health problems of US and British children, the same firms are setting their sights on a lucrative market in Asia, the world's most populous region.
Krispy Kreme's marketing machine is proving irresistible to Japanese teens.
"Krispy Kreme is the epitome of how to cram maximum calories into the smallest amount of food," Gill said. "All you can do with doughnuts is to point out what crap they are."
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