Food Deserts

In which I argue that not only desserts but also deserts are corrolated with obesity.

What is a food desert? That’s “desert” as in “Sahara,” not the sweet thing you eat at the end of a meal. According to Wikipedia, it's

any area in the industrialised world where healthy, affordable food is difficult to obtain,

specifically associated with low income. There is a good amount of debate about whether such things even exist. The problem, as I see it, is that this definition is very subjective: One can always have access to high quality or nutritional food if one is willing to spend enough time to travel to it. If a person lives a couple miles away from a grocery store but has "access" via expensive (to them) public transport, does that constitute "access"? Technically, of course, yes. But what I really think the question should be:

Is there any statistical correlation between proximity to full-service grocery stores, obesity, and poverty?

I think the answer to that is "yes". Answering why is a much more difficult (and perhaps open) question. Read on to hear my reasoning.

This was inspired by a recent blog post on a similar topic by my friend Matt (of cooking fame) who is currently working on his Ph.D. in Policy and Management at CMU.

Nearly 13% of all households in Washington D.C. were struggling with hunger in 2007–2009. The district is divided into wards, much like townships. According to D.C. Hunger Solutions,

Wards 7 and 8, which have the District’s highest poverty rates, also have the city’s highest obesity rates and are home to large “food deserts.”
Of the city’s 43 full-service grocery stores*, only two are located in Ward 4, four in Ward 7, and three in Ward 8. By contrast, Ward 3—the highest-income Ward—has eleven full-service stores.

* There are lots of stores—especially in big US cities—that call themselves “grocery stores” that are really bodegas or convenience stores; they don’t sell much in the way of groceries, and usually don’t sell anything in the way of fresh produce or raw meats. I interpret a “full-service grocery store” to be any store that sells fresh produce, raw meats, and perhaps fish.

Ward 8’s poverty rate in 2009 was 35%. I couldn’t find an exact statistic for the area of Ward 8, but it appears to be at least 1/8th the area of the entire district, which is 100 square miles (260km2). Assuming each of the ward’s three grocery stores services an equal 100/8/3 ≈ 4 square mile area, I think it is plausible that a good number of the ward’s residents live at least one mile from a supermarket.

A mile walk to a grocery store isn’t really very far, right? The problem is that, at least in urban environments, there are usually much more convenient and much less healthy options that are closer. Why would I walk 2+ miles to buy some veggies, fruit, and raw ingredients if I could walk to the end of my block and get a prepared fast food hamburger or fried chicken for likely the same price? (When I lived in a not-so-savory part of Philadelphia, I could buy a whole fried chicken at the end of my block for the same price as a raw chicken from the 1-mile-away grocery store). And if one is already obese, that walk to the store is even harder.

Many of these urban centers have extensive public transport systems that would allow car-less residents to commute back-and-forth to a supermarket. Here are some counter-arguments:

  • For people that live below the poverty line (the average per capita income in Camden, NJ, for example, is less than $12k), a public transit ride for as little as $3 is a significant expense. It is likely even more expensive in DC.
  • How many shopping bags can one person reasonably carry home without a car? Enough for a week’s worth of food for a family of four? I know that at least extrapolating from the way I shop, I’d have to make multiple trips per week to feed a family of 4, which is a further expense.
  • Many of these factors are likely social/cultural in nature, however, that only speaks to the underlying cause; it does not change the fact that there is a correlation between availability of produce, obesity, and poverty.

Townsend, et al., did a study on the correlation between food insecurity and obesity. Here is a summary from Oregon State University:

[Obesity] may also result from periodic episodes of food insecurity. For many people, food stamps and money for food run out before the end of the month. Among respondents to the 2004 Oregon Hunger Factors Assessment, 95 percent ran out of food stamps at least 1 week before the end of the month. When money and food stamps become available again, some may overeat low-cost, high-calorie foods that have limited nutrient density. This could result in gradual weight gain over time, especially for mothers with dependents in the household.

In conclusion, I think it is safe to say that food deserts do exist, and they’re correlated with poverty and obesity.

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