Obesity, once mainly the scourge of the West, is spreading its tentacles into Asia, threatening health systems and economic growth.
One of the world's leading experts in the field, Eric Finkelstein, says obesity－with all its associated health problems such as diabetes, high blood pressure and heart disease－is a major problem "that is only going to get worse". The research professor of global health at Duke-National University of Singapore says Asia's growing obesity problem is due largely to Westernization.
Western fast foods and processed foods have taken hold in many parts of Asia, replacing traditional foods.
Finkelstein says that while some countries in Asia have implemented programs to try and curb the growth in obesity, "the reality is that it is very difficult for governments to combat obesity … there are just too few policy levers".
As to the impact on health systems and the economy, he says it is hard to quantify.
"We know from US data that obesity is responsible for 9 per cent of healthcare expenditures," he says.
"This is much lower in Asia as the prevalence remains lower, but costs continue to creep up. Obese individuals also have higher rates of absenteeism, so there are additional costs to employers."
The Obesity Prevention Source at the Harvard School of Public Health says in a recent report that treating obesity and obesity-related conditions costs billions of dollars a year.
A study conducted by Cornell University in 2012 says the United States, which has the worst rate of obesity in the world, spent $190 billion a year on obesity-related healthcare expenses.
"The enormity of this economic burden and the huge toll that excess weight takes on health and well-being are beginning to raise global political awareness that individuals, communities, states, nations and international organisations must do more to stem the rising tide of obesity," the report said.
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 per cent of the world's obesity. China and India together represent 15 per cent. 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 per cent in India and 1.3 per cent in Indonesia to 13.8 per cent in Mongolia and 19.3 per cent in Australia.
In women, the lowest rates were found in India (0.6 per cent), China and Japan (both 3.4 per cent), with the highest rates in Australia (22.2 per cent) and Mongolia (24.6 per cent).
"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 Organisation'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."
He explains that the costs to healthcare systems from all non-communicable diseases are already high, and projected to rise in the future.
"The increasing burden of NCDs－such as diabetes and heart disease－imposes severe economic consequences that range from impoverishment of families to high health system costs and the weakening of country economies. "The NCD epidemic is thwarting poverty reduction efforts and robbing societies of funds that could otherwise be devoted to social and economic development," Lindmeier says.
Research at the Duke Global Health Institute and Duke-NUS Graduate Medical School in Singapore estimated childhood obesity costs around $19,000 per child when comparing lifetime medical costs to those of a normal weight child.
When multiplied by the number of obese 10-year-olds in the US, lifetime medical costs for this age alone reach roughly $14 billion.
An alternative estimate, which takes into account the possibility of normal-weight children gaining weight in adulthood, reduces the cost to $12,900 per obese child. The findings appear in the journal Pediatrics.
"Reducing childhood obesity is a public health priority that has substantial health and economic benefits," says Finkelstein from Duke-National University, who is lead author of the report.
"These estimates provide the financial consequences of inaction and the potential medical savings from obesity prevention efforts that successfully reduce or delay obesity onset."
Obesity is a known risk factor for a wide range of diseases, including cardiovascular disease, Type 2 diabetes and certain cancers. Roughly one in three adults and one in five children in the US are obese, according to the Centers for Disease Control and Prevention.
"Public health interventions should be prioritized on their ability to improve health at a reasonable cost," Finkelstein says.
"In order to understand the cost implications of obesity prevention efforts, it is necessary to accurately quantify the burden of childhood obesity if left untreated."