People all over the world, especially in the West, are getting heavier. Global obesity rates have doubled since 1980 according to new research published in the journal The Lancet.

During 1980, 4.8 percent of men and 7.9 percent of women were obese. Three decades later, those percentages increased to 9.8 percent of men and 13.8 percent of women in 2008.

More than one in ten people in western nations are now considered obese.

Among the developed countries, Americans weigh in as the heaviest and the Japanese are the slimmest.

Being obese puts people at a greater risk of developing certain "fat cancers," like breast and colon cancer. The number of cancer cases is also climbing.

"Sadly, changing ways of life, such as reduced physical activity, are making people unhealthier and in turn prone to such diseases as cancer," Dr. Eduardo Cazap, president of the Union for International Cancer Control, said in a statement released by the World Health Organization.

Researchers said that around 340,000 cancer cases could be prevented each year in the U.S. if more people ate better and kept their weight down.