• Myths, Presumptions, and Facts about Obesity

    There’s a paper out now at NEJM that’s just so awesome. Myths and obesity? What more could you want:

    BACKGROUND: Many beliefs about obesity persist in the absence of supporting scientific evidence (presumptions); some persist despite contradicting evidence (myths). The promulgation of unsupported beliefs may yield poorly informed policy decisions, inaccurate clinical and public health recommendations, and an unproductive allocation of research resources and may divert attention away from useful, evidence-based information.

    METHODS: Using Internet searches of popular media and scientific literature, we identified, reviewed, and classified obesity-related myths and presumptions. We also examined facts that are well supported by evidence, with an emphasis on those that have practical implications for public health, policy, or clinical recommendations.

    RESULTS: We identified seven obesity-related myths concerning the effects of small sustained increases in energy intake or expenditure, establishment of realistic goals for weight loss, rapid weight loss, weight-loss readiness, physical-education classes, breast-feeding, and energy expended during sexual activity. We also identified six presumptions about the purported effects of regularly eating breakfast, early childhood experiences, eating fruits and vegetables, weight cycling, snacking, and the built (i.e., human-made) environment. Finally, we identified nine evidence-supported facts that are relevant for the formulation of sound public health, policy, or clinical recommendations.

    CONCLUSIONS: False and scientifically unsupported beliefs about obesity are pervasive in both scientific literature and the popular press.

    There were some myths that I already knew were false. But the presumptions pretty much blew me away. Early childhood weight and habits predicting later outcomes? No evidence. Eating more fruits and vegetables? No effect on their own. Snacking associated with weight gain? Nope. Built environment related to obesity? Try again.

    Granted some things about obesity are correct. Exercise is good for you no matter what, and it can help in long term weight loss. Programs that involve families are more likely to help children. Bariatric surgery can be a real life saver for some people.

    Go read the whole thing (if you can – I don’t know if it’s gated). I’m constantly amazed at how little of what we think we know is true actually is.


    • I also enjoyed that article.

      Note that the “built environment” could be related to obesity, since it was one of the author’s “presumptions” not a myth. In the paper, the authors suggest that there have been no randomized trials looking at the built environment’s role in obesity. There have only been inconsistent associations in observational studies.

      I’d also question the use of overly broad terms like “built environment”, since there is likely heterogeneity in the results based on what you’re considering.

      • That’s fair. But I can’t tell you how many activists and policy makers pushing adding parks as the silver bullet for fixing obesity, with little evidence behind them. I’m more than happy to be proven wrong, but I want to see some research that’s better!

        • yeah i agree with that.

          I would guess it’s rather difficult to randomize components of the built environment. You’d have to convince policy makers to do it, and not many communities would want to be the “control group”. But who knows, maybe Oregon will do like they did with Medicaid…

          • I wonder if anyone has ever offered the same dollar amount to two sets of communities to do two things that don’t interact so that each set is the control for the other on a different intervention. For instance, communities randomized to group A get money for their built environments. Communities randomized to group B get the same amount of money for more police. It’s possible many communities would rather take money for just one or the other than to get no money at all. Key assumption is the policing doesn’t affect obesity and the built environment doesn’t affect crime. If that’s a bad assumption, can we swap out policing for something else of interest that does obey this type of orthogonality?

            • The problem with built environment is that much of it is subjective. For example, most studies show no relationship between objectively measured access (usually distance) to parks and other physical activity opportunities and actual physical activity or obesity. But there is a decent and consistent relationship between subjective measures of access (e.g., “Do you have good access to places to be physically active?”) and PA/obesity.

              The issue, then, is getting to the heart of what makes something accessible. Policy is a part of it; a study in LA found that, in neighborhoods where schools were locked on the weekends, kids were less physically active than in neighborhoods where schools were open. Appearance is a part of it; people don’t go to crappy, run-down parks. Safety is a part of it. Programming and staffing are parts of it, where applicable. Accessibility is a part of it;t it’s nice to have sidewalks, but not if they don’t lead anywhere.

              There needs to be more research around this, but also a recognition that it might be different in different communities, and therefore less apt to easily turn up through research.

              By the way, I believe there are the same issues and considerations around food access/food deserts.

    • Thanks for the link. Like a lot of mental health, obesity has become one of those issues where the public space has become crowded with bad and erroneous messages that hold their appeal because they’re filled with terms and assumptions that we’re supposed treat as inherently virtuous (prevention, community, development, etc).

    • Neat article. The list of funding/potential conflicts of interest is pretty scary though. It includes McDonald’s, Coca Cola, Jenny Craig, and Kraft, along with many others. That’s not reason to disagree with their conclusions, but it’s certainly deserving of closer scrutiny. Certainly, some of those funders would have financial interest in debunking certain ideas that their products are thought to be causes of obesity.

      • Good catch by Eric on the disclosed potential conflicts. Per the NYT article:

        -Weight loss is greater with programs that provide meals.
        -Some prescription drugs help with weight loss and maintenance.
        -Weight-loss surgery in appropriate patients can lead to long-term weight loss, less diabetes and a lower death rate.

        These “facts” have a different meaning when you consider these researchers receive funding and consulting fees from Jenny Craig, GSK, Merck, Novo-nordisk etc.. Again, not to say the findings aren’t true, but these companies do stand to gain material from such findings, and they just so happen to provide income to the researchers. Maybe I’m naive and this is par for the course in medical research, but it sure seems a bit sketchy.

        Reminds me of the Washington Post’s coverage of GSK’s influence on supposedly “peer reviewed” drug studies, available at http://wapo.st/Tj7BVh.

        • I saw the conflicts. They were published by the article.

          Please explain how food and beverage companies stand to gain from this work. Seems to me that much of the lobbed criticism against this comes from diet interests that absoltuely stand to lose from this work.

          I’ll give the point about drugs, but that was a minor, minor point in the article. The rest?

    • Having had a chance now to read the whole thing, I don’t think that most of it will come as much of a surprise to folks deeply involved in the obesity prevention arena. Three thoughts:

      1. The one big surprise for me was about breast-feeding. That’s been such a core focus that it’ll be very interesting to see how it’ll change.

      2. There’s a huge caveat in the physical education finding: it’s about PE classes “in their current form.” Certainly nobody thinks that standing in line for 20 minutes, then climbing a rope for 2 minutes, will affect obesity. But curricula designed to maintain MVPA for 25-30 minutes at a time, 5 days a week, should be more effective. When well-implemented. So it’s hard for me to see this as a myth; shouldn’t it be in the presumptions category? Otherwise, they (and we) really need to emphasize the “in their current form” element of this to advocate for better curricula, not just more PE time.

      3. Can we all agree to not tell our partners and spouses about the sexual activity finding? Some myths are better left perpetuated.

    • This is in keeping with my views that we really do not know much beyond the basics about nutrition and overweight .

    • Great comments. Interesting paper and the comments about the “built environment” are bang on.
      Have you read the disclosure statements? The list of demons supporting the authors of this special article is illustrative.
      The “funders” are also the builders and perpetuators of the built environment and the products they make are the root cause of the health crisis.

      I am sure glad I don’t believe in conspiracy theories.