On the grounds of the Bodyworks weight loss campus in Beijing, 30 tubby men and women sweat profusely, gasping for air as they pound the treadmills in an exercise room.
They represent a shocking new statistic in the world's most populous country.
According to some estimates, a third of China's population -- some 429 million -- are overweight or obese and thus prime candidates for heart disease and diabetes.
China is growing fatter faster than any developing nation except Mexico, with grave implications for the work force and for economic growth in the world's second biggest economy.
At the Bodyworks campus, participants range in age from 7 to 55 and come from across China. Each pays 30,000 Yuan (about $4,700) for the six-week program.
For that, they get balanced meals and exercise for six hours each day. The regimen includes weight training, running, yoga and football.
"For the first two to three weeks, it was especially hard. I cried on the phone to my parents and told my father, 'I can't make it,'" said Zhang Fang, a 28-year-old employee with China Unicom from northern Shanxi province.
"My mother said: 'If you don't continue, you're finished. You need your health.'"
When Zhang joined the camp, she weighed 150 kg (300 pounds), had high blood pressure and had trouble breathing when she walked. She's lost 50 kg (110 pounds) in one year.
"Now I'm a fat person, but at least I'm not a super-sized fat person," Zhang said.
Though most Chinese think a chubby child is a healthy child, society can be less tolerant of overweight adults, who complain of not being able to find jobs.
"I want to give people a good impression when I go for interviews," said Zheng Xiaojie, a 22-year-old university student from far-western Xinjiang. She lost over five kg (11 pounds) in seven weeks. "People feel more comfortable about thinner people."
More acute in big cities Obesity is most acute in China's biggest urban cities such as Beijing and Shanghai, where people enjoy higher incomes, eat richer foods and lead more sedentary lifestyles.
"Urban China got richer. It's just gone out and bought itself more food and bought itself cars and couches to sit on while watching TV," Paul French, co-author of "Fat China: How Expanding Waistlines Are Changing a Nation," told Reuters.
Mu Ge, the sales manager at Bodyworks, said the most glaring difference between China and other countries "is that the rich people in China are all extremely fat ... (whereas) in other countries, the wealthy are all very thin and beautiful."
"In the U.K., only the poor people will eat junk food and will therefore be fat," Mu said. "In China, it's the opposite. The more money you have, the fatter you are. It's almost as if it's proof that living standards have improved."
Dressed in an oversized T-shirt that did little to conceal his rotund belly, Liu Chi has lost more than 10 kg (22 pounds) since he first entered Bodyworks six weeks ago and now weighs in at about 90 kg (198 pounds).
To Liu, his progress represents a new lease on life, one he hopes will include a girlfriend and fewer taunts.
"I had an inferiority complex," said the cherub-faced 20-year-old student from Hebei province. "People will look at me on the streets and ask me: 'How heavy are you?'"
Sharp spike Ding Zongyi, a professor at the Chinese Medical Doctor Association, who has been studying obesity in China for the past 30 years, said the obesity rate jumped 158 percent from 1996 to 2006 and is set to rise further.
Even by the most conservative assumptions, the rate of overweight and obese people in China will double over the next two decades, Barry Popkin, professor of nutrition at the University of North Carolina, wrote in the July/August 2008 issue of the journal Health Affairs.
Health experts say that the speed with which China is putting on weight is alarming.
"In America and Europe, they had to go through the whole process of inventing supermarkets and processed food," French, the writer, said. "It took stages in the West. The Chinese didn't have to invent the Mars bar. It was given McDonald's, KFC, Tesco and Walmart."
KFC parent Yum Brands Inc. says the Chinese market is its main earnings driver, and McDonald's said China has been the fastest-growing market for the firm worldwide in terms of the number of new restaurant openings.
Popkin said in emailed comments that more fried food, consumption of food from animal sources, sugared drinks and too few vegetables have contributed to China's expanding waistlines.
Although the prevalence of fast food is a major culprit, extra-high amounts of salt, sugar and oil in Chinese cooking is another factor contributing to the sharp rise in obesity.
And while China's obesity rate is still half that in the United States, the U.K. and Australia, it has led to a worrying rise in chronic non-communicable diseases such as cancer, strokes, heart disease and diabetes.
In a growing number of developed nations, obesity is fast replacing tobacco as the most important preventable cause of chronic non-communicable diseases, health experts warned.
About 12 percent of children aged 7 to 18 in China are overweight or obese, Popkin said.
The number of people suffering from diabetes has reached 92 million in China, almost 10 percent of its population of 1.3 billion, according to a March 2010 study in the New England Journal of Medicine.
In China, the economic costs of obesity are enormous, Popkin said. An increasingly obese population poses economic problems in terms of treatment costs, paid sick leave, loss of productivity, disability and premature death.
The indirect effect of obesity and obesity-related dietary and physical activity patterns was 3.58 percent of GDP in 2000 and was projected to reach 8.73 percent in 2025, Popkin wrote.
"These estimates do not account for much of the recent rapid increase in the use of and spending for pharmaceutical products, which would make the total costs even higher," he wrote.
Ding said there had been no action taken by the government to address the problem.
"The government pays little attention to obesity partially because many parents and even doctors still lack the awareness to recognize and seriously cope with obesity as a problem," he said.