We did it, America!

According to a new report from the United Nations Food and Agricultural Organization, the United States is no longer the world's fattest developed nation―Mexico is.

Nearly a third of Mexican adults (32.8 percent) are considered obese—people aged 20 and older whose body mass index (BMI) is 30 and above. That edges out the United States, where 31.8 percent of American adults are considered obese.

Syria at 31.6 percent, is the third fattest among developed countries, while Venezuela and Libya are tied for fourth at 30.8 percent.

Mexico's urban lifestyle and rising income levels coupled with malnourishment among the country's poor have helped it claim this unhealthy title.

“The same people who are malnourished are the ones who are becoming obese,” Abelardo Avila, a physician with Mexico's National Nutrition Institute, told the Global Post. “In the poor classes we have obese parents and malnourished children. The worst thing is the children are becoming programmed for obesity. It's a very serious epidemic.”

Diabetes kills an estimated 70,000 people a year in Mexico—"or roughly equal to the deaths authorities say are caused by more than six years of the country's gangland wars," the Post noted.

About 12 percent of the world's total population is obese, according to the U.N. report.

The world's fattest nation overall is Nauru, a South Pacific island where a staggering 71.1 percent of its 10,000 inhabitants are obese.

The U.N. report does not include data for American Samoa, which has been tabbed in the past as the world's fattest country. According to a 2010 World Health Organization report, nearly all of that Pacific island's inhabitants (95 percent) are considered overweight.

On the other end of the scale is Japan, the thinnest developed country. Just 4.5 of Japanese adults are considered obese, the U.N. says.

Prevalence of obesity among adults in developed countries (% obese)

Rank Country Rate 1 Mexico 32.8 2 United States 31.8 3 Syria 31.6 4 Venezuela 30.8 4 Libya 30.8 6 Trinidad & Tobago 30.0 7 Vanuatu 29.8 8 Iraq 29.4 8 Argentina 29.4 10 Turkey 29.3 11 Chile 29.1 12 Czech Republic 28.7 13 Lebanon 28.2 14 New Zealand 27.0 14 Slovenia 27.0 16 El Salvador 26.9 17 Malta 26.6 18 Panama 25.8 18 Antigua 25.8 20 Israel 25.5 21 Australia 25.1 21 Saint Vincent 25.1 22 Dominica 25.0 23 United Kingdom 24.9 23 Russia 24.9 25 Hungary 24.8

Source: United Nations Food and Agricultural Organization's 2013 State of Food and Agriculture Report