"In 1980, less than 40 percent of Mexican women were overweight. By 2008, almost 70 percent were. In some Pacific Island nations, more than 90 percent of men are now considered overweight. The Middle East is also seeing a boom in chubbiness."
People like fattening foods, and when they can get them, they'll probably eat them, and they're going to tend to get fat. It's no mystery. The link goes to NPR.org, where there's a photo with the caption: "Government workers exercise at their office in Mexico City, August 2013. To counter the obesity epidemic, the city requires all government employees to do at least 20 minutes of exercise each day."
The top-voted comment over there is: "Can you imagine the backlash if the US government ordered all employees to do 20 minutes of exercise per day? People would scream about the waste of taxpayer money." I think what people would scream about is the government telling people what to do.