A study by the University of Washington's Institute for Health Metrics and Evaluation said 46 million Chinese adults were obese and 300 million were overweight.

Although China does have a problem, it is still way behind the US, which accounts for 13 percent of the world's obesity. China and India together represent 15 percent.

The Congress of the Asian Pacific Society of Cardiology was told last year that overeating, sedentary lifestyles, cultural attitudes and lack of prevention programs are to blame for the rise in obesity in Asia Pacific.

"In many of the countries in Asia Pacific, the malnutrition problem nowadays is not under-nutrition, it is over-nutrition, which has resulted in overweight and obesity," cardiologist Sim Kui Hian says.

The prevalence of obesity in men ranged from 0.3 percent in India and 1.3 percent in Indonesia to 13.8 percent in Mongolia and 19.3 percent in Australia.

In women, the lowest rates were found in India (0.6 percent), China and Japan (both 3.4 percent), with the highest rates in Australia (22.2 percent) and Mongolia (24.6 percent).

"Asia Pacific has developed rapidly, and technological advances mean that children now spend too much time on the Internet and mobile devices so they don't take up much physical activity," says Sim.

"The Asian culture revolves around food as a way of showing hospitality because in the past there was a lot of famine. As a result, there is a cultural perception that if you're not fat or obese then you are not well-off," he said.

Researchers say obesity in Asia can be tracked along with the region's economic growth over the last 30 years.

Western fast food and processed foods are rapidly taking over traditional fresh foods in many countries, especially in middle-class households.

Rob Moodie, professor of public health at the Melbourne School of Population Health, University of Melbourne, says that as Asian people become more affluent, their "lifestyle and eating patterns change with them".

"Fast food and processed foods take over from fresh produce bought at the local market and prepared at home," he tells China Daily Asia Weekly, noting that food has become something of convenience.

"What we see in Asia today is good nutritional food being replaced by food rich in fats, sugar and oils.

"Wander around regional airports, railway stations and office blocks, and you will find vending machines full of sugar-rich drinks, while Western fast-food companies have already begun marching across the region."

The problem, however, is not confined to the middle classes. The poor are targets, too, Moodie says.

"You only have to look at the poor in a developed country like Australia to see the trend. For them, fast food is convenient and above all cheaper than a good nutritional meal and you don't need to prepare it. It is a quick and cheap way of relieving hunger."

Mark Wahlqvist, emeritus professor of medicine at Monash University, says: "I think the emphasis should be on the fact that it (obesity) is growing in Asia."

Speaking to China Daily, he says that "in time, obesity will be a major burden on healthcare systems" in the region, but as yet there is little data available.

This is confirmed by the World Health Organization's spokesman for the Western Pacific region, Christian Lindmeier, who says: "Specific data on the impact of obesity on health services do not exist for our region."