China is expected to overtake the US in the coming years as the world's biggest economy, and it is fast closing in on another first with the rising rate of obesity among its citizens.

Chinese citizens' waistlines are quickly expanding as they indulge their growing affluence.

Just 20 years ago, back when most Chinese city dwellers were still pedaling bicycles to work and few could afford lavish, fat- and sugar-laden meals, not many were seriously overweight. By 2010, though, about 38.5 percent of all Chinese 15 or older were either overweight or obese, up 54 percent from 2002.

For a country familiar with famine, the abundance of affordable food for most Chinese is an unimagined luxury. But it is a mixed blessing, for diabetes and other health problems associated with obesity pose a daunting challenge for the country's health system.

Weight Watchers International, Inc, the world's leading weight management service company, made little headway after setting up a China joint venture in 2008 with Groupe Danone of France and began revamping its strategy in July 2011.

While Chinese increasingly are emulating American lifestyles, their unique habits and attitudes make it a very different and difficult market. "We decided to review the strategy. It was a joint venture and it was not working as we had hoped," says Bruce Rosengarten, Asia Pacific president for Weight Watchers International.

The market is potentially a huge one. China, with its 1.3 billion people, may well soon have more obese people than the US, with its population of 311 million.

According to the World Health Organization, among Chinese over 15, 45 percent of males and 32 percent of females are overweight or obese. Combined, the nearly 40 percent of overweight Chinese add up to some 500 million people. Among Americans, about 78 percent are overweight or obese.

"It is a growing, serious problem in China, but it is not as bad as in the US or other Western countries. There are a lot of fit people as well as a lot of unfit people in China," says Sheldon Dorenfest, CEO of the Dorenfest China Healthcare Group, a Chicago-headquartered health care investing and consulting company.

Focus on figure

In tackling China, Weight Watchers faces two main problems: its own inadequate understanding of the Chinese market and the unexpectedly different attitudes among its clientele toward what a healthy weight loss program should entail. "People see weight loss only in terms of shaping their figures," Rosengarten says.

He says Weight Watchers' foray into the Chinese market so far has been something of a laboratory experiment in learning about how different the market is. "We have to understand how they eat and how much they eat; how they cook their food. We also have to understand how their lifestyles changed in term of snacking, increased wealth and the influence of Western lifestyles. People no longer ride bicycles - the shift to a sedentary lifestyle has been quite significant."

The usual doctor's orders for a change of diet and more exercise tend to fall on deaf ears, says Paul French, chief China market strategist for the UK-based Mintel Group and co-author of a book titled, "Fat China, How Expanding Waistlines Are Changing China" (2010).

Weight Watchers is still revamping its China strategy, and Rosengarten declined to provide annual revenues or other operations-related figures.

The company has two shop-front operations in Shanghai, holding 45 meetings per week in that city, four or five meetings a week in Beijing and three in Nanjing in Jiangsu Province.

The company's approach of promoting weight loss through healthful habits, eating smarter and getting more exercise has yet to take hold.