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Why solving the "food desert" problem won't make people automatically eat healthier

May 4, 2015

There's an idea that's taken hold in the past few years about why it is that poor people, on average, eat less healthy food and have higher rates of obesity. The idea is simply that people in neighborhoods marked by poverty lack access to healthy food choices. Somewhere along the way (most likely starting in the U.K.) a person with an ear for good marketing decided to label these kinds of neighborhoods "food deserts."

Now, there's even a public service announcement dedicated to ending food deserts in the U.S.

The 2014 Farm Bill called for spending $125 million to attack food deserts by funding new stores or markets to sell fresh fruits and vegetables in low income areas. But this year, Congress decided to strip funding for the program

A new economic study argues this may have been the right decision. 

The study, titled "What Drives Nutritional Disparities? Retail Access and Food Purchases Across the Socioeconomic Spectrum," was published as a working paper today by the National Bureau of Economic Research. 

The first question the paper tries to address is whether food deserts even exist. Some have argued all people in so-called "food deserts" really lack is access to large, chain grocery stores. These people say low-income neighborhoods still offer plenty of healthy food choices at neighborhood stores and markets. 

So, in this new paper, three researchers hailing from the Wharton School, Princeton University and the USDA, took a deep look at what's actually available on store shelves across the country: 

Using geo-coded data on the location of over 200,000 retailers across the U.S., we first document that there are large disparities in the concentration of stores across neighborhoods with different socioeconomic profiles. We then use weekly store-level sales data from Nielsen to identify the products that are available at over 30,000 participating retailers between 2006 and 2011.

Sure enough, when they looked at what's actually on the shelves inside those 30,000 stores, the disparities in healthy food options across neighborhoods looked less dramatic. But a "small, statistically significant" difference in options does exist. Food deserts aren't a complete myth. 

But the paper finds that, even when fresh, healthy foods are available, people of lower socioeconomic status are less likely to choose those options. And the largest predictor of that difference may not actually be the person's income level, but their education level. 
 

If you could wave a magic wand and suddenly solve the food desert problem, you'd only close the gap in healthy eating by 3%, at most.

Still, with fewer options available, the question remained whether the introduction of new stores could change behaviors. To address that question, the researchers looked at what actually happened in neighborhoods where new stores opened. Then, they extrapolated those results in a calculation to see what might happen if all low-income neighborhoods suddenly had the same options for healthy food as high-income neighborhoods. They conclude that this change would result in healthier behaviors, but it would only close the gap by 1-3%. 

So, if you could wave a magic wand and suddenly solve the food desert problem, you'd only close the gap in healthy eating by 3%, at most. 

In conclusion, the researchers write: 

Overall, these results indicate that the nutritional quality of household purchases responds very little, if at all, to changes in retail environments. This suggests that policies which either encourage the entry of new stores offering healthy foods or encourage existing retailers to offer more healthful products will do little on their own to resolve socioeconomic disparities in nutritional consumption.

If solving the food desert problem won't do much to help people eat healthier, what will? This paper doesn't offer an answer to that question. But its authors do note that they hope to take up the question of food affordability in their future research. It may be that, even when healthy options are available, low-income or less-educated consumers don't choose that food simply because that food is more expensive. 

If that turns out to be the case, it suggests food policy should be directed more at making healthy food affordable. At any rate, just making that food available doesn't seem to be enough.