American Health Fail: What’s Making Us Fat? A Decline in Smoking

Americans are fat. The latest obesity estimates reach as high as 30% of the population; and the future looks worse. There’s been much hand wringing over the years, with a new television show sprouting up every season imploring the obese to lose weight.

A new paper by researchers Charles Baum and Shin-Yi Chou provides a detailed look at the leading indicators of weight, using the National Longitudinal Survey of Youth from 1979 and 1997 to compare the habits, similarities and differences between people of the same age – just a quarter century apart.

The results aren’t pleasant: the largest effect on our recent weight gain? The decline in cigarette smoking.

Here’s the abstract:

We simultaneously estimate the effects of the various socio-economic factors on weight status, considering in our analysis many of the socio-economic factors that have been identified by other researchers as important influences on caloric imbalance: employment, physical activity at work, food prices, the prevalence of restaurants, cigarette smoking, cigarette prices and taxes, food stamp receipt, and urbanization. We use 1979- and 1997-cohort National Longitudinal Survey of Youth (NLSY) data, which allows us to compare the prevalence of obesity between cohorts surveyed roughly 25 years apart. Using the traditional Blinder-Oaxaca decomposition technique, we find that cigarette smoking has the largest effect: the decline in cigarette smoking explains about 2% of the increase in the weight measures. The other significant factors explain less.

The researchers examined differences in employment, physical activity at work, food prices, prevalence of restaurants, cigarette smoking, cigarette pricing, food stamp receipts and the prevalence of urban sprawl.

They found that:  “(i) occupational fitness and strength demands significantly affect weight, (ii) cigarette smoking (and being a cigarette smoker) significantly decreases weight, (iii) food stamp receipt significantly increases weight, and (iv) urban sprawl significantly increases weight.” The decline in cigarette smoking, however, only makes up about 2% of weight increase, and the authors saw their criteria show only small percentage changes in weight measures as a whole, as opposed to other studies with much higher numbers.

The authors write: “Ultimately, the socio-economic and demographic factors examined in this analysis, whether considered individually or collectively, explain a minority of the increase in BMI, overweight, and obesity.”

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  1. Joe Dokes says:

    The study confuses correlation with causation. The summary itself clearly states that only 2% of the rise in obesity can be linked to a decrease in smoking.

    Thus, blaming the decline in smoking is just wrong, the real reason people are fat is that over the past 30 years we’ve been lied to, we’ve been told that FAT makes us fat and that we should eat carbs. Wrong, carbs make us fat. As the poster above stated read Gary Taubes Good Calories Bad Calories, or Why We Get Fat, for the real causes of American obesity.

    The study itself shows this, who is most likely to be obese? People on food stamps. Why, because the have to eat cheap, what’s cheap? Food loaded with cheap processed carbohydrates.


    Joe Dokes

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    • Mike B says:

      Calories make you fat, doesn’t really matter where they come from. There are a lot of issues that come together here, but the truth is that cigarettes suppress appetite (wonder while ballerinas all smoke?) and cigarettes provide a narcotic hit to the brain. Eating sugar, fat and salt also provides a narcotic hit to the brain and with all the current price incentives (cigarettes = expensive, unhealthy food = cheap) it’s no surprise that people are eating themselves to death the same way they used to smoke themselves to death. The only difference is the time between getting sick and dropping dead.

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      • Joe Dokes says:

        I used to believe that as well. I always thought of it as a simple equation, calories in vs. calories out. Turns out I was wrong, to sum up 600+ pages in Taubes and others books it boils down to carbohydrates ability to quickly and dramatically raise blood sugar that induces both additional hunger and fat storage.

        For me personally since I cut way back on my carbs, particularly refined carbs, I’ve dropped 35 Lbs. without ever being hungry. Prior to that I tried Jenny Craig and a couple of other diets in which I was simply STARVING all the time with minimal weight loss.


        Joe Dokes

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    • Enter your name... says:

      Something that explains a small fraction of the change is still linked to it.

      Think of it this way:

      Imagine that you have $100 in your wallet. If I steal $98 from your wallet, and someone else steals $2, did the other person not steal anything, merely because their theft only explains 2% of the change to your wallet’s contents? Or are they still linked to the change?

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  2. Statspotting says:

    It is interesting how you cover one study after other with different fallacies, this one is a classic case of narrative fallacy.

    ““Our need to fit a story or pattern to a series of connected or disconnected facts”

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  3. bsod says:

    every smoker knows to expect weight gain if and when they quit smoking, this concept alone is not really news.

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  4. crquack says:

    How do you explain the dramatic rise in childhood obesity? I doubt smoking has much to do with that.

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  5. PreemptivePlacebo says:

    The smoking rates for adult men peaked at about 60% sometime in the 1950s.

    Today about 66% of adults are overweight or obese.

    67% of the population drinks alcohol while 33% consider themselves total abstainers.

    Two-thirds of the adult Americans population placed some kind of bet last year.

    Smoking, over-eating, drinking and gambling are all examples of maladaptive coping mechanisms.

    Walter Mishcel’s Stamford Marshmallow study on the psychology of self-control found that about 66% of the kids in the study were unable to self-impose delayed gratification.

    That 2/3rds number keeps popping up.

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    • James says:

      I’ll challenge at least your drinking alcohol as (exclusively) a coping mechanism. Most of us who drink consider alcoholic beverages to be just another food group. I might have a glass of wine with my dinner, or perhaps milk or juice. I might have a beer on a hot summer day, or a glass of iced tea. The choice is made entirely on taste & availability. So why would the choice of the wine or beer be a coping mechanism for the majority of us?

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  6. Guestspeaker says:

    Great Blog. I will raise one issue however:

    Have you guys (the Freakonomics team) considered making a small tab with an explanation of econometrics? I know you explain it in accessible terms in the books, but I just keep seeing the words “correlation” and “how can you tell from correlations” and “what about this factor, it explains everything” in the comments here.

    The whole point of Freakonomics is to get at causality using robust econometric techniques, but some of the comments seem to reflect a serious lack of understanding on the part of the readers about the methodologies used in the studies.

    People: there are indeed multiple causes for shifts in social phenomena. Econometrics (e.g. here on panel data) (1) shows what % of the variance is explained by a particular variable, such as the change in smoking, and (2) controls for hosts of other causes, which ultimately tries to simulate a controlled experiment. I keep seeing anecdotes here from posters – but again, the point of Freakonomics is that using econometric techniques on lots of data often turns our anecdotal notion on its head.

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  7. Lainey says:

    I quit smoking a year ago and gained like 80 lbs. It’s not good. I also have a very sedentery desk job, so that doesn’t help either.

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