The North American Free Trade Agreement's liberalization of trade policies has allowed the United States to export obesity to Mexico, according to an April 5 study co-authored by David Wallinga '83. The report, which was published in the International Journal of Occupational and Environmental Health, suggests that the exportation of American goods such as processed food, corn and soybeans contributed to a 12 percent increase in obesity in the Mexican population between 2000 and 2006.
An individual's food environment, or the nutritional resources available, influences dietary habits, according to Wallinga, who conducted the research with Karen Hansen-Kuhn, Sophia Murphy, Sarah Clark and Corinna Hawkes, his peers at the Institute for Agriculture and Trade Policy. The number of unhealthy foods and convenience stores selling such foods in an individual's vicinity affects the individual's likelihood of gaining weight, he said.
"What we found is that there has been a change in obesity in Mexico, and it looks a lot like the obesity epidemic in the United States," Wallinga said. "The Mexican food environment has evolved to resemble the unhealthy American food environment."
An analysis of international trade policies and obesity rates in Mexico revealed that obesity rates began to increase shortly after NAFTA's inception in 1991, Wallinga said.
"If you look at the timeline of when people in Mexico started getting more overweight and obese, it coincided with NAFTA, so we wanted to dig deeper and see how changes in obesity coincided with changes in trade policies," he said.
NAFTA's loosening of trade regulations between the U.S., Canada and Mexico allows for an open flow of goods between the three countries, including food products detrimental to human health, Dartmouth geography professor Susanne Freidberg said. As a result, Mexico can import the products it does not produce itself or cannot produce cheaply.
Since 1991, Mexico's importation rates of corn, soybeans, sugar, artificial sweeteners, processed foods and livestock products has increased, Wallinga said. The corn and soybeans are processed into high fructose corn syrup and hydrogenated vegetable oil, respectively, he said.
Increased consumption of processed dairy products, soft drinks, processed meat and ready-to-eat snacks high in fats and sweeteners can also be traced to the increased availability of these goods in the country, according to Wallinga.
"Mexico is exporting what we call healthy foods and importing more unhealthy foods," Wallinga said.
NAFTA has also directly affected the Mexican economy by pitting the goods of small-scale farmers against mass-produced American goods in the marketplace, according to the study. Many farmers cannot compete, creating a rise in unemployment.
In addition, NAFTA altered foreign investment rules, intensifying American investment in the Mexican food supply chain, Wallinga said. Beverages, oilseed processing and processed foods are the largest recipients of American investment, and investment in livestock production is also surging, according to the study.
Liberalized free trade policies have allowed U.S.-based fast food retailers such as McDonald's to expand into Mexico, which is the largest regional market for Yum! Brand, Inc., the owner of Kentucky Fried Chicken, Taco Bell, Pizza Hut and Long John Silver's.
Obesity annually costs at least $170 billion in direct medical fees and reduces productivity, Wallinga said.
"Major policies like NAFTA and trade agreements in general are devised without really thinking about the health implications," Wallinga said. "We're saying that, Hey, obesity is a really expensive problem for any country to try and address.'"
The study was conducted over a period of approximately two years and is a continuation of the Institute for Agriculture and Trade Policy's research, Wallinga said. Data was obtained from the United States Department of Agriculture's Global Agricultural Trade System and various sources of Mexico-specific data.
The rise in obesity may be linked to additional economic factors, according to Dartmouth economics professor Doug Irwin.
"I don't know if they can directly attribute the change in diets to the reduction in tariffs on U.S. food as opposed to the rising incomes of Mexicans that make them more like Americans in terms of their eating habits," Irwin said. "So the question is how much of their result is due to NAFTA per se as opposed to other causes."
Rising obesity rates in Mexico also raises concerns about the presence of food deserts, in which residents of poor urban neighborhoods must turn to unhealthy eating habits as a result of limited access to fresh foods, according to Freidberg. Ultimately, the underlying force of the institute's study is an "environmental determinist argument," she said.
"I don't think that the causes of obesity are so clear-cut," Freidberg said. "It's important to note that there are far-reaching consequences of NAFTA for people's health and well-being in Mexico, but that doesn't necessarily mean that there's a direct link between the importation of junk food and the rising obesity rate."
Wallinga said he pursued his interest in the intersections between health, food and agriculture in medical school and emphasized the importance of environmental programs at the College.
"The study makes clear why things like the Dartmouth Organic Farm and agricultural issues in general should be a little more integrated into the academic curriculum of an Ivy League school like Dartmouth," he said.
