The United States loses a distinction it's had for years. Our country is no longer considered the fattest country in the world. That title now goes to our neighbors to the south. A new report from the United Nations Food and Agriculture Organization says Mexico is now the fattest country in the world. 32.8% percent of Mexican adults are considered obese. In the United States it's 31.8%, Syria is listed as third with 31.6%, and Venezuela comes in at number four.