New paper on global obesity

We have a new paper out in the World Health Organization Bulletin looking at the association between an increase in food supply and average weight gain:

Stefanie Vandevijvere, Carson C Chow, Kevin D Hall, Elaine Umali & Boyd A Swinburn. Increased food energy supply as a major driver of the obesity epidemic: a global analysis, Bulletin of the WHO 2015;93:446–456.

This paper extends the analysis we did in our paper on the US food supply to the rest of the world. In the US paper, we showed that an increase in food supply more than explains the increase in average body weight over the duration of the obesity epidemic, as predicted by our experimentally validated body weight model. I had been hoping to do the analysis on the rest of the world and was very happy that my colleagues in Australia and New Zealand were able to collate the global data, which was not a simple undertaking.

What we found was almost completely consistent with the hypothesis that food is the main driver of obesity everywhere. In more than half of the countries (45/83), the increase in food supply more than explains the increase in weight. In other mostly less developed nations (11/83), an increase in food was associated with an increase in body weight although it was not sufficient to explain all of the weight gain. Five countries had a decrease in both food and body weight. Five countries had decreases in food supply and an increase in body weight and finally three countries (Iran, Rwanda, and South Africa) had an increase in food but a decrease in body weight.

Now by formal logic, only one of these observations is inconsistent with the food push hypothesis. Recall that if A implies B then the only logical conclusion you can draw is that not B implies not A. Hence, if we hypothesize that increased food causes increased obesity then that means if we see no obesity then that implies no increase in food. Thus only three countries defied our hypothesis and they were Iran, Rwanda, and South Africa where obtaining accurate data is difficult.

The five countries that had a decrease in food but an increase in body weight do not dispute our hypothesis. They just show that increased food is not necessary, which we know is true. Decreased activity could also lead to increased weight and it is possible that this played a role in these countries and the 11 others where food was not sufficient to explain all of the weight increase.

I was already pretty convinced that food was the main driver of the obesity epidemic and this result puts it to rest for me. This is the main reason that I don’t believe that the obesity epidemic is a health problem per se. It is a social and economic problem.

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13 thoughts on “New paper on global obesity

  1. How much of this is driven by:

    1) Improved Food production technologies lowering the production cost and shifting the food supply curve to the right.

    2) Changes in food distribution practices, e.g. increased portion sizes as a move towards profit maximization independent of changes in demand.

    3) Increased food demand.

    Note that all three can be interdependent as well.

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  2. @Rick It is mostly 1) and some of 2). Food marketing has also improved which has probably led to 3). However, the excess food did not come from excess demand. Too much food came first and demand then followed. We know this because food waste has increased as well.

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  3. interesting–i wonder if i buy this paper do i get like a free salad or something? i was going to buy some food today up the street but i’m too scared–almost got killed yesterday–i think they call this july 4th. i know a good obesity plan—i did this 2 or 3 years ago—u call up your relatives to say hi, so they decide for your birthday something is wrong, take you to the hospital for say 3 days. turns out to be 6 weeks and u come out looking like a concentration camp survivor, all for only 3500$ /day which i didnt pay since i had no insurence. then u carry an oxygen tank for 2 months. they also had all this interesting technology —i could see a camera sticking a needle into my heart, put one through my back—it was pneumonia. those peope are experts—-many of them–all very nice— had like 40 differebt people, but i didnt get any morphine or dilaudid—they said all u get is tylenol based on my his/story, my bed neighbor did.i saw movies about the amish, captain ahab-melville. rolling stones playing for obama at white house, one time the cleaning lady who wanted me to marry her cut off my life support by mistake, another time i was trying to fill our some forms with my family and i lost oxygen but they got it back.

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  4. @rgerkin I would say that is entirely the cause of the obesity epidemic. Increasing food supply increased consumption of food. I guess “food push” is not catchy enough?

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  5. i wonder how you define ‘food supply’. i’m not dealing on a global scale, only the more scientific ‘anecdotal’ approach. one goes downtown or to my relatives—and they have plenty of food, a whole foods market, stuffed frig, juice, etc and they arent obese tho some could perhaps lose 5 or 10 lbs. i go up here, and there is plenty of food too—mcdonald’s, potato chips, liquor (perhaps a kind of juice including calories in it)–and in this area i would say people are often a bit obese. is a calorie a calorie? do you just weigh it—all the palm oil. soy oil, corn syrup, etc.? 5 lbs of sugar = 5 lbs of oranges?

    i like say’s law. its obvious, except you have to throw out the motivation part—its an identity, not a statement about utility functions, risk aversion, behavioral economics or other excess verbiage.

    but you need to update it via SMD theorem (sonnenschein—had a job as president of u chicago, mantel, debreu) .

    obesity is not a health problem? rather, a social and economic problem? one can use paraconsistant logic, nonstandard logic, etc. maybe social and economic problems are a health problem, possibly mental health. eg addicted to growth, affluenzia… maybe phillip morris company could fund some more talks up at NIH on ‘chaos theory in the brain’ to see if one can disentangle the causality (eg granger causality). i think its more like a ‘tangled web’ (s j gould)

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  6. @ishi Food supply is total amount of food that is available for humans. So it excludes crops lost to pests and fed to domestic animals and includes imports minus exports. Not sure what you mean by Say’s law is obvious, you mean obviously not always true? “Calorie is a calorie” means that the body does not care where the energy comes from. It does not mean that a pound of oranges is the same as a pound of sugar since oranges are mostly water. What it means is that a calorie from an orange is equivalent to a calorie from sugar or fat or anything else. The low carb people believe that a calorie from sugar can cause more weight gain than a calorie from fat or protein.

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  7. i mostly agree with that. a calorie is a calorie. i sometimes drink diet coke —large bottle 2 liters–so i dont have to make coffee or tea so i can get my caffeine (which i dont really need) to get going. but sometimes i pick up the wrong bottle—regular coke (loaded with sugar). so it has 500 or 1000 calories and i am completely nonfunctional—i pass out. if i buy oranges they may have the same calories but i can’t do them all at once. also, there are ‘nonlinear effects’—oranges also have some nutrients like vitamin c. a calorie is a calorie but opium is not heroin and chewing coca leaves in bolivia is not the same as smoking crack in dc.

    as for say’s law, its an identity or conservation law (a la Noether’s theorem or even say a Hamiltonian—eg see ‘symmetry and invariance in economics’ https://pages.stern.nyu.edu/~rsato or related things on gauge theory of economics (illinski, arxiv) or at perimiter instiute (canada, smolin, weissmman)

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  8. ps–you dont need the https:// just
    pages.stern.nyu.edu/~rsato (other blog i sometimes read from nyu is andrew gelman–alot of nyu i dont like—niall ferguson–his story, richard epstein’s ‘law’)

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  9. say’s law has so many interpretations its almost meaningless.

    its been extensively discussed on the blogs ecological headstand (tom walker aka sandwichman ) and ‘econospeak’ (where walker also posts, and started i think by economist of JMU j barkely rosser—son of the math logician rosser who invented the lambda calculus). etc (brad delong…)

    rosser was quite critical of krugman since his noble prize in economic geography did not cite very similar papers published years before —‘ohhh i didnt know’—they were in economic geography journals by people into ‘chaos and complexity theory’ and even i had read them, but they didnt come from the ivy league). krugman does worry about inequality so he has noble prize money, tenure, and an opinjon column which i rarely read (the ann landers or dan savage of economics, along with paul samuelson of the Washington Post—who is not an economist tho there is a very great one with the same name).

    krugman also wrote a column long ago i read saying the ‘anti-free trade protestors’ (eg battle of seattle, wto/imf/wb) didnt know what they were talking about. (Free trade is always a pareto improvement since, following rawl’s theory of just us, it benefits me—redistribute the wealth, cut welfare). Paul samuelson, whose ‘stolper-samuelson theorem’ (also cited by Krugman in a scientific american article arguing for ‘free trade’) wrote a paper in AER (am econ review) before he died saying that theorem was not applicable to the real world (eg it assumes 0% unemployment, market clearing, perfect information etc just like say’s law, and robert lucas and milton friedman (nobles in econ —their research papers were on rational expectations and ‘free to choose’ (or lose) so their policy suggestion was ‘let them eat cake’. )

    Krugman also wrote a paper in JPE 95 (j political economcy) on ‘symmetry breaking’ (which had approximately zero mathematical content—he probably heard the term somewhere) which showed that under some conditions ‘free trade’/globalization could lead to greater inequality (sortuh like the effects of NAFTA). His conclusion was that while theoretically possible, it was highly unlikely, so we would all be better off by liberalizing the labor markets and having the drug cartels put their profits into J P Morgan chase, donald trump etc. (This is like the conclusion of the book published either by regnery or the washington ‘moonie’ examiner–before they found pluto—‘the invisible hand’ by ingrao and israel—economic equilibrium in the his(or her)story of science’. (on amazon) . General equilibrium exists, as proved by arrow, debreu and hahn in the 50’s using fixed point theorems and perron-froebenius theorem (and later disproved by debreu, hahn and arrow—SMD) . The problem with it is you can’t effectively find the equilibrium point.

    As I pointed out on econospeak and ecological headstand in my comment on say’s law last year (which they conveniantly deleted) another version of that law (which as pointed out by rosser neither originated with say nor was believed by him nor phrased in the usual ‘supply creates its own demand’ way) ‘peace sells, but who’s buying?’ I still believe in say’s law—its like the hamiltonian for general relativity (or even ‘wave function of the universe’–gel-mann wheeler etc) . The total energy of the universe is a conserved quantity and an identity and equal to zero. Im going on a hike at gettysburg tomorrow, not chatanooga.

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  10. ps actually the article by krugman i mentioned is called ‘globalization and the inequality of nations’ co-authoried with venables in quarterly journal of economics 95. ‘symmetry breaking’ is only discussed in the appendix. (the 3 big econ journals i think are aer, jpe and qje and the rest are specialistic—econometrica, income….JEBO etc.) discussion of krugman’s noble by barclay rosser is on brad delong’s blog oct 13 2008 toward the end. i’m considering entering the republican primary, using the trump card (i already have 2 metro smart cards). its going to be a bipartisan campaign, so i’m also entering into the democratic primary (say by by hilary bernie malley). this way people get a choice for either demo or repubgnant or to vote twice.

    i wonder what people think of walter freeman in neuroscience. eg
    http://www.arxiv.org/abs/q-bio/0511037

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