There’s an interesting article at the New York Times that goes into some detail on an unforeseen effect of NAFTA on Mexico—the obesity rate has soared:
Mexico began lifting tariffs and allowing more foreign investment in the 1980s, a transition to free trade given an exclamation point in 1994, when Mexico, the United States and Canada enacted the North American Free Trade Agreement. Opponents in Mexico warned that the country would lose its cultural and economic independence.
But few critics predicted it would transform the Mexican diet and food ecosystem to increasingly mirror those of the United States. In 1980, 7 percent of Mexicans were obese, a figure that tripled to 20.3 percent by 2016, according to the Institute for Health Metrics and Evaluation at the University of Washington. Diabetes is now Mexico’s top killer, claiming 80,000 lives a year, the World Health Organization has reported.
There are several aspects of this story that I wonder about. The first is that I can’t help but wonder if the writer of the article isn’t romanticizing the past? Here is the authors’ description of the diet of their example family back in the 1960s:
The family’s experience in food service began in the 1960s, when Mr. Ruiz’s grandmother sold tamales and home-cooked food made with produce from a nearby farm; those same ingredients sustained her boys with vegetable stews, beans, tortillas and eggs. Meat was a luxury.
Were people actually eating that way or is that how they might have eaten? Mexico’s per capita income in 1960 was about half what it is now in real terms which made it a poor country by international standards. Were a lot of Mexicans just going hungry? It does not seem to me that we should romanticize poverty or, at least, we shouldn’t selectively romanticize poverty.
What changes have occurred in the distribution of rural and urban population in Mexico and what are the differences in nutrition between rural and urban populations?
They don’t mention the change in the prevalence of deficiency diseases over the period at all. Vitamin A deficiency, for example, has declined by nearly 70% over the period. In 1960 malnutrition was a leading cause of death in Mexico. Malnutrition while still a factor there has declined markedly over the period.
As my pathologist buddy says, everybody dies of something. As the rate of death due to malnutrition and deficiency diseases declines, the rate of death due to diabetes, cardiovascular problems, or cancer increases.
My second observation is that I strongly suspect that people adapt to the diets that they eat over time and vice versa. There are obvious examples of this. More than 90% of Western Europeans retain the ability to digest dairy products into adulthood (“lactose persistence”). Among the Bantu of South Africa the phenotype enabling individuals to digest dairy is nearly unheard of. Dairy products are an important component of the Western European diet; it is not among the Bantu.
Fifty years is just too short a time for that sort of adaptation to take place. Importing food takes place much more quickly. It may be that Mexican people have made choices to eat things that aren’t what their ancestors adapted to eat—as is the case with us as well.
I suspect that things like the amount of protein required in the diet varies based on ethnicity. It could be that I would starve on the diet with which a South Indian would flourish. And vice versa. I suspect that with the widespread availability and low cost of genetic testing we’ll have much more knowledge on this topic very quickly.
On the first point, what stands out to me is that my mother-in-law’s family moved to Arizona in the 19th century and tamales were always a special occasion meal that took multiple hands all day to fix. OTOH, the great thing about beans is that their cheap, versatile and don’t require that much attention.
On the second point, the other example of ethnic constraints that comes to mind is the Indian famine at the outset of WWII. The rice crop failed in the rice belt and the British helped ship wheat from the wheat belt, which was apparently not digestible by weak and famished rice-eaters. On a related note, I do wonder if the growth of gluten-free products is based upon changing ethnicity, new dietary knowledge or fads.
Might be fun to plot the obesity rate vs American retailer growth in Mexico, forex, Walmart has about a 20% market share there.
There are lots of things that would be fun to study in this. Consider, for example that the prevalence of diabetes in the United States differs widely by race/ethnicity with Native Americans having by far the highest incidence. Note that “Hispanic” is a linguistic community not a race or even an ethnicity. Americans of Mexican descent have a higher prevalence of diabetes than those of Cuban descent. Then there’s this older study with a number of interesting findings:
I have some methodological issues with the study and think it should be repeated with more rigor but it’s suggestive.
My working hypothesis would be, just as I suggested in the post, that the issue in Mexico is probably multi-factorial including obesity, diet, and genetics with genetics playing the most significant role.