With an adult obesity rate of 31.8%, the United States is the most obese of the world’s developed countries, according to a report by the Food and Agriculture Organization of the United Nations.
As of 2008 – the year considered in the report – the Czech Republic was second in obesity among the developed world, with an adult obesity rate of 28.7%, the Food and Agriculture Organization said in "The State of Food and Agriculture 2013."
The most obese country in the developing world – in the entire world, in fact – was the Pacific island nation of Nauru, with an adult obesity rate of 71.1% and an overall population of around 10,000. The second-most obese country in the world was another tropical Pacific nation, the Cook Islands, with an adult obesity rate of 64.1%.
The report defined obesity as a body mass index of 30 kg/m2 or higher and considered adults to be anyone over age 20. The United Nations categorizes approximately 25% of countries as the developed world, which consists of all of Europe, northern America (Bermuda, Canada, Greenland, Saint Pierre and Miquelon, and the United States), Australia, Japan, and New Zealand.