BOSTON _ Obesity is no longer just an American problem. The whole world _ thanks to Western food and Western ways _ is getting fatter, too. And fast.

The World Health Organization's latest survey shows that in the last seven years, the obesity rate has shot up from 12 percent of the world's population to 18 percent. The study covered 93 countries, including the United States, where more than 60 percent of Americans are now considered overweight.

"Changing lifestyles and changing diets have caused an epidemic of obesity around the world," University of Rhode Island anthropologist Marquisa LaVelle said Saturday.

In a series of reports to the American Association for the Advancement of Science in Boston, anthropologists said the problem cuts across national borders and cultures _ but appears to stem from a common cause.

From New Guinea to South Africa, people are eating more and exercising less _ a prescription for greater girth that America has been practicing for decades.

Researchers say the emergence of Third World couch potatoes may be an inevitable consequence of the migration of rural populations to the city, where they are less likely to engage in daylong manual labor. But the cities also expose them to rich calorie-laden foods that aren't available in rural areas.

'`The McDonaldization of the world has allowed this wave of obesity to proceed faster than before,'' says University of Oxford anthropologist Stanley Ulijazek. ``Changes like this, which occur in the course of a generation, are too swift to be based on genetics.''

Scientists say a cruel irony of the trend is that obesity is on the rise in many areas of the world where famine and chronic under-nutrition are still major killers. The dichotomy means that some countries may have to contend with a wave of obesity-related health problems, such as diabetes and heart disease, even as they struggle to feed millions of people who don't have enough to eat.

　　From Healthy.net