With globalization, U.S.-style fast food has become commonplace in East and Southeast Asia. The study looked at more than 60,000 Singaporeans of Chinese descent.

"Many cultures welcome (Western fast food) because it's a sign they're developing their economics," said Andrew Odegaard, from the University of Minnesota School of Public Health, who led the study.

"But while it may be desirable from a cultural standpoint, from a health perspective there may be a cost," he told Reuters Health.

The study participants were interviewed in the 1990s, then followed for about a decade.

Participants were between 45 and 74 years old at the outset. During the study period, 1,397 died of cardiac causes and 2,252 developed type 2 diabetes.

Those who ate fast food two or more times a week had 27% greater odds of diabetes and 56% higher risk of cardiac death than those who ate little or no fast food, the researchers found.

Among 811 subjects who ate Western-style fast food four or more times a week, the risk of cardiac death rose by 80%.

The findings held even after the researchers adjusted for other factors that could influence health, including age, sex, weight, smoking status and education level.

In fact, the Singaporeans who ate Western fast food often were more likely to be younger, educated and physically active, and were less likely to smoke, than those who stuck to a more traditional diet.

Odegaard's team found that Eastern fast foods, such as dim sum, noodles and dumplings, were not associated with more cases of type 2 diabetes and cardiac deaths.

"It wasn't their own snacks that was putting them at increased risk, but American-style fast food," he said.

The profile of the fast food eaters differs markedly from that of the average fast food consumer in the United States, he added, with eating fast food in countries like Singapore a status symbol and a way of "participating in American culture".

The findings hold serious implications for recently developed and emerging countries, said Sara Bleich, an assistant professor of health policy at Johns Hopkins Bloomberg School of Public Health in Baltimore.

"The big multinational fast food companies are increasingly looking to maximize profit outside the United States, and they're looking to emerging economies like Singapore to do that," she said. "So at the global level, the health implications are very strong."