More Evidence of the Link Between Obesity and Food Prices

(Photo: Håkan Dahlström)

“Our findings suggest that increases in the real price of one calorie in food for home consumption and the real price of fast-food restaurant food lead to improvements in obesity outcomes among youths.  We also find that an increase in the real price of fruits and vegetables has negative consequences for these outcomes.”

That’s from a new paper (abstract; PDF) by Michael Grossman, Erdal Tekin, and Roy Wada, called “Food Prices and Body Fatness among Youths.” Here’s the entire abstract:

In this paper, we examine the effect of food prices on clinical measures of obesity, including body mass index (BMI) and percentage body fat (PBF) measures derived from bioelectrical impedance analysis (BIA) and dual energy x-ray absorptiometry (DXA), among youths ages 12 through 18.    The empirical analyses employ data from various waves of the National Health and Nutrition Examination Survey (NHANES) merged with several food prices measured by county and year.  This is the first study to consider clinically measured levels of body composition rather than BMI to investigate the effects of food prices on obesity among youths.  We also examine whether the effects of food prices on body composition differ by gender and race/ethnicity.  Our findings suggest that increases in the real price of one calorie in food for home consumption and the real price of fast-food restaurant food lead to improvements in obesity outcomes among youths.  We also find that an increase in the real price of fruits and vegetables has negative consequences for these outcomes.  Finally, our results indicate that measures of PBF derived from BIA and DXA are no less sensitive and in some cases more sensitive to the prices just mentioned than BMI.

For more on the causes and consequences of youth obesity, see our podcast “100 Ways to Fight Obesity.”

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  1. Nick says:

    Is this really in contention? More expensive food means people eat less, news at 11.

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  2. rationalrevolution says:

    Which is exactly why we should be taxing junk food and subsidizing healthy food. Except in reality we know that a large portion of US farm subsidies go to “unhealthy” foods, or at the very least go toward crops that are easily and regularly used to make unhealthy foods (corn, sugar, etc.) (Although in the case of sugar its a very complicated issue because sugar farmers both receive subsidies that bring down the price of sugar and they get federal price supports that drive up the price of sugar, so its a contradictory mixed bag).

    But what is certain is that fruits and vegetable get zero or almost zero farm subsidies, while staples (which comprise a base of junk food) are heavily subsidized. In addition meat is also heavily subsidized.

    I think we should certainly remove all subsidies for meat production and let the price of meat rise, as well as dairy perhaps.

    We should then shift our subsidies from stables to fruits and vegetables (not completely removing subsidies from staples).

    Lastly we should apply post processing taxes to end products based on health evaluation, with taxes put on unhealthy food (or low nutrient/high calorie food).

    Hot debate. What do you think? Thumb up 23 Thumb down 19
    • Enter your name... says:

      We have different ideas about what’s healthful. If I were trying to improve the consumption of healthful foods, I’d personally kill all direct and indirect price supports for grains and processed foods (like those frozen vegetables with gloppy, salty, greasy sauces), but encourage the consumption of fruits, vegetables, dairy, and meat.

      But that’s because my health issues are about carbs. Someone with sky-high cholesterol would probably want cheap whole-grain products but no cheese or sausage. And someone with an ethical or religious issue about animal products wouldn’t care about doughnuts (which are both fatty and carby) but would want milk and meat to be unsupported.

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    • MITBeta says:

      Except that intelligent people will disagree on the scope of what constitutes “junk food.” For example, I’ll agree with you that corn and most corn based products are junk, but I disagree that meat is. Further, I find most modern fruit has WAY too much sugar in it, and might as well be advertised right next to the donuts.

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      • Jake says:

        We also have to be more specific about the word “meat.”

        From what I can find on the internet, there is substantial evidence that consuming red meat and pork increases the risk of getting heart disease, obesity, and certain types of cancer. On the other hand, consuming fish seems to lower the risk of all three of those things (provided you eat a low-mercury species). I can’t seem to find anything useful on the consumption of poultry.

        If anyone has contradicting evidence or info on poultry, I’d really appreciate hearing it so I can adjust my diet accordingly.

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      • MITBeta says:

        @Jake: You’re confusing the words “evidence” and “correlation”. And then you’re further confusing “correlation” with “cause”. There are lots of studies out there (whose conclusions…) correlate heart disease and red meat and/or pork consumption with heart disease, but there is no “evidence” that this is actually true. In fact, none of these studies adequately isolates the red meat variable to a statistically significant degree. Sometimes they do, but the researchers don’t like what they find. Here’s a nice analysis of a recent study the correlates red meat and cancer that concludes that red meat is bad for you, but the data actually shows that it’s not:

        And chicken you say? Well, it’s an indisputable fact that chicken consumption has quintupled! in the US since the 1940s, yet Americans are now suffering from so much obesity that it’s now considered a disease. Surely it must be the chicken! See how correlation works there?

        Don’t be so sure about everything you read on the internet, since you can find any argument to support your preconceived notions. Please question what you’ve been told is true for the last 35 years (since the Food Pyramid was first published) and then look at what the result has been. And then go research why people who are eating their 6-11 servings of grains per day, cutting their fat intake, cutting their red meat intake, exercising more, and eating more chicken are now fatter and more insulin resistant than ever.

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    • Tracy says:

      I already wrote this elsewhere. Make a plug-in cell phone gadget so that farmers’ markets can accept SNAP money (food stamps) for produce, and this will support the small farmer also.

      Thumb up 1 Thumb down 0
  3. Dorothy Sorensen says:

    Seems to me people themselves need to drive the demand for in general healthy food which will in turn make for farmers willing to provide more healthy food (food that avoids raising cholesterol, high blood pressure, and diabetes). I’ve noticed over the years, as we’ve become more aware of the types of foods that do this more of these sorts of foods are now available, such as salmon burgers and sweet potato fries. While sweet potato fries are still fries, they are better than regular white potato fries. My point being these weren’t on the market even 5 years ago, thus a demand for more healthy choices created a market that supplied these preferences.

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    • MITBeta says:

      The problem with this idea is that our very government has been promoting EXACTLY the kinds of food that does all the things you suggest we avoid. When the USDA has an agenda to push corn, is it any wonder that you find high fructose corn syrup in nearly everything? Is it any wonder that the food pyramid foundation is grains, pastas, and other processed carbohydrates?

      Contrary to popular belief, Americans have been trying to eat well for the last 35 years, dutifully following government advice. Unfortunately, it’s the advice that’s broken, not the adherence to it.

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  4. Ana G. Csiky says:


    Thank you for this interesting article. As a Venezuelan living abroad since 1996, I have always been shocked when I go back home. What strikes me is that the worse our economy gets, the fatter the average Venezuelan becomes.

    Though stereotypes would like to show that poor people eat less, the reality is that they simply eat cheaper. Most depressed parents will eat more as a last source of emotional entertainment and try to feed their kids well in an attempt to “provide as much as possible”. In a country where basic staple food products are often missing from the market shelves this means buying more junk when you find it.

    Also, when tap water is no longer drinkable and bottled water is more expensive than a bottle of beer or coke, clearly Coca-Cola’s sugary best-seller takes the lead towards national obesity.

    -Ana G. Csiky
    A concerned fan of the books, the blog & the podcast

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  5. Sheela Alex says:

    When Steven Levitt talks about his love for KFC and McDonalds, I cringe. ‘Foodstuffs’ that are strangely tasty, cheap and filling may work for some: but for most of us – not so much. The ultra-processed, chemically enhanced (for taste!), and preserved nature of fast foods likely has more to do with obesity than the balance of carbs/proteins/sugars/fats.

    In my experience of having once been 45 lbs overweight; eating less processed foods leads to less-indulgence. Laboratories work hard to create the perfect “mouth feel” – a real phrase for what they are going for – to increase overconsumption of processed foods. This is a significant part of the problem.

    Please find more studies like this! I’m sure you’ll find increasing evidence that may help people (except, of course, Steven Levitt) stay closer to foods which may cost a bit more – but which are closer to their original – and far less addictive – nature.

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