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 percent 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 organizations must do more to stem the rising tide of obesity," the report said.