A new global analysis says almost a third of the world is fat, and no country has been able to curb obesity rates in the last three decades.

Researchers at the Institute for Health Metrics and Evaluation at the University of Washington have found that more than 2 billion people worldwide are now overweight or obese, and the highest rates are in the Middle east and North Africa.

The head of the study, Christopher Murray, says he and colleagues reviewed more than 1,700 studies covering 188 countries from 1980 to 2013. He says, "When we realized that not a single country has had a significant decline in obesity, that tells you how hard a challenge this is."

The study was paid for by the Bill and Melinda Gates Foundation and published online today in the journal, Lancet.

[Associated Press]