Correlation, causation, and food deserts
June 10, 2012 9 Comments
Nice long post by Sarah Kliff in Wonkbook about existing research on food deserts (areas without easy access to healthy food) and Philadelphia’s attempt to eradicate them. Despite all you might have heard of food deserts in poor communities, there’s actually no evidence that they in any way cause obesity, rather:
a growing body of research has questioned its basic assumption: that people will eat better if given better options. Multiple studies have scoured local, state and national data looking for a causal relationship between weight and access to healthy food. None has found it…
Public health researchers have long known that lower socioeconomic status correlates with worse health, including higher levels of obesity. Numerous studies have also noted connections between access to healthy foods and lower weight. A 2011 article in the Journal Obesity Review found that “greater accessibility to supermarkets or less access to takeaway outlets were associated with a lower prevalence of obesity.”
If governments could improve proximity to healthy foods, the theory went, it could reduce a rapidly rising obesity rate.
Kliff points out that the theory has not been able to be particularly well tested, but insofar as it has, there’s not been any evidence for a causal relationship. Poor communities having higher rates of obesity for many reasons and they fewer supermarkets and more take-out outlets. But there’s no reason to believe these factors are causing the obesity– this may be a perfect example of a spurious correlation.
Wrigley conducted one of the first studies of a food desert intervention, looking at what happened when a grocery store was brought into an underserved part of Leeds, an industrial city in northern England. Of shoppers surveyed, 45 percent switched to the new store. Their habits, however, barely changed: Consumption of fruits and vegetables increased by one-third of a cup per day — about six grapes or two broccoli florets.
“The results came out quite small, a very modest increase in consumption of nutritious foods,” Wrigley says. “It seemed an almost nonexistent improvement.”
Similar research in the United States shows much the same.
The amount of healthy food I personally have had in my diet has varied tremendously over the years and I’m pretty damn sure (yes, I know I am an N of 1) that access had absolutely nothing to do with it. Also, you want a “cheap” food” Bananas are an absolute steal! I cannot believe how cheap they are. And a bag of Gala apples is amazingly affordable, too. People aren’t choosing to not buy these foods over price issues.
I’ve become persuaded that the government really should play a role in combating obesity. I’m just skeptical of whether attempts to eliminate food deserts will do much on that score. But, hey, as a good liberal, I’m open to evidence. If the Philadelphia experiment works– great; if not, we’ll know that we need other approaches.
About Steve Greene
More evidence that libs want the government to be your daddy and take away choices
And repubs just want to take away reproductive rights. And take away marriage rights. And choices of what Gods to worship. And where. And force everyone to worship at school, weather they want to or not. And take away the right to clean water, air and food. And take away a future without major climate change.
Repubs just want to remove all the REALLY important choices.
We can’t control the climate and no one is for polluted air, water or environment. No one is taking away marriage rights, gays never had them to begin with. Most repubs support civil uniions which grants them the same rights instead of bastardizing marriage. How about NAMBLA and taking away their sexual rights to young boys
how does providing greater access to a wider variety of food choices equal being one’s daddy and taking away one’s choices? greater access means great choice…right?
regarding efforts to provide oases in food deserts–even if a lack of access to healthy food isn’t causing obesity, what harm is there? while many remediation efforts are plagued by the scourge of unintended consequences, it’s hard for me to see any here–not even the threat of putting locals out of business, as the residents in food deserts are not served by locally owned businesses to begin with.
the truth is that whatever plagues a given society is always most prevalent and most virulent among the socially disadvantaged. the real cause of obesity among the poor is poverty and all the attendant ills that accompany it, not the least of which is that the poor are practically drowning in stress hormones, like cortisol–and stress hormones do cause fat depostion. the same effects are seen across primates species–no primates copy well with inequality, especially if they happen to be the primate at the wrong end of the iniquitous stick.
the other factor is corn–corn is the great fattener–it fattens everything that eats it–and the diet of the american poor is nearly 100% corn (in some form or other). the percentage of corn in the diet decreases as you climb up socioeconomic class ladder.
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See fooddesertrs.org for more on UK food deserts
I mean fooddeserts.org, ooops a typo
I wonder if home economics courses are still being taught in school as mandatory courses?
Its been my experience that lots of people need to be taught how to cook good food economically.
Its much cheaper to eat unprocessed food then otherwise.
For example, a box of kraft dinner may seem cheap, but its mostly starch. You can buy a 10kg bag of parboiled rice around here for $14.95, and it will last a LONG time. Rice is easy to make and can be fixed up with various proteins and vegetables thousands of different ways. Rice will expand to three times its raw size. 250 ml (1 cup) of raw rice = a serving for two for two days.
The same can be said of plain macaroni, spaghetti, egg noodles, although rice is still the king of cheap foods. A package of minute rice or “Rice a Roni” will last at most a week, and cost five times as much per serving.
The only thing processed food generally gains you is time, various chemicals and salt. Lots and lots of salt.
I usually make ten days worth of any particular meal, eat two days worth and freeze the rest.
When people find out they can eat much better quality food that tastes better for less money, many choose that over processed or fast food without any government intervention.
Look at that. “libs” (whatever that is) aren’t out to control everything everyone does. Apposed to every republican who ever lived who want all the non rich people to die quietly in a corner so they can sell our meager possessions on the open market.
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I’ve always been skeptical of the food desert argument. I’ve never seen a grocery store — whether in a city, a suburb or a rural area — that doesn’t sell fresh produce and frozen vegetables and dry legumes and grains at reasonable prices.
In fact, convenience food is more expensive per serving and more available at larger groceries that locate in wealthier areas (not surprising, since wealthy people can afford it).
It’s not that this food is not available. It’s not that it’s more expensive.