Weight loss

There is a lot of talk in the science blogosphere about weight loss these days. People are talking about their own personal experiences, which are interesting and can start up some good discussions. I have stayed out of them because 1) I’ve been busy and 2) it’s not my place to judge what other people do with their bodies. But bloggers are also posting some questionable scientific support for the benefits of weight loss and dangers of being fat, which are murky at best*… Anyway, I have confused feelings about the whole thing. I support FA and believe pretty strongly that the scientific evidence is much more mixed than the one-sided story generally pushed in the news. Lots of the studies that are spun to present evidence of extreme dangers/costs/impacts from being fat are actually very inconclusive without the spin. A lot of the statistical methods used in the studies that appear more conclusive are pretty much crap. We just don’t know that much, and there is a vested interest in keeping popular opinion firmly in favor of one point of view, science be damned. And scientists are people and are products of this society, too, and it’s hard not to mix your personal experiences into your scientific viewpoint. But a lot of people read science blogs (and Scienceblogs) as a kind of non-peer-reviewed scientific source on many subjects, so I wish other results were getting a little more attention there.**

* I’ll just link to Sandy’s whole series, if that’s all right with you.

** Though I kind of wish that about peer reviewed literature, too. When you design a study to examine possible relationships between health risks and obesity, and deliberately choose a sample pool of fat people with health problems, ignoring all of the healthy fat people (most of them), it’s awfully easy either for you or a journalist to turn around and lazily conclude that all fat people have health problems. There are some methodological problems there.

12 Responses

  1. What is frustrating is that if you want to understand human health, you need to have a more global perspective — what are the cancer rates, life spans, incidences of heart attack, etc, in other parts of the world? How do they live, what do they eat, how do they move, and how fat are they? Where I work in another part of the world, my subjects are as fat as Americans (about the same average BMI) but have lower breast cancer rates — by a lot. The reason? They move more — a lot more. They eat to accommodate that movement, which keeps them an equivalent weight, but they are perfectly healthy, if not more healthy, than us.

    Weight bears only a small relationship to health, and only in large scale studies. How healthfully you live is far more important.

  2. But how do you know even that’s the reason? What if they just have a lower herditary risk factor?

    The body is not a bunsen burner, and it just is NOT as simple as calories in/calories out. That group might have a similar weight distribution because their genetics are to have to similar weight distribution. It seems likely that exercise and food are variables that mainly impact short-term body size changes, and 60-80% of the factors contributing to body size on any time scale are inherited.

    Also, when it comes to cancer, environmental factors, like harmful pollutants, for example, also have an impact.

  3. Yeah, I’ve noticed that, too. It’s not on the blogs I read most often, but I saw it pop up in the sidebar and followed it all, and… man. I’m not entirely sure where I stand – I’m about 95% FA and agree with the studies that show most problems are comorbidities rather than causally related, but I think there sometimes can be some health-related issues with weight for certain individuals. (And did you see the big spread in Time last week showing that – gasp! – exercise doesn’t usually lead to weight loss?) I’m a bit sad at the way that the whole diet craze is sweeping Scienceblogs, but I don’t know that I have the energy to go try and fight against it, either. I’m hoping it dies down in the next few weeks.

  4. I also don’t really feel like it’s my place to go in and be all judgy that people want to diet. Also, there are not enough hours in the day to attempt that against the whole internet, you know? Isis’ post today really bothered me so I commented, but I’m trying to stay out of it and be really respectful of the fact that these are other people’s lives and it’s not for me to say what they should and shouldn’t do.

    But the science presented has been very one-sided, so I kind of want to put another voice out there, fwiw.

  5. Exactly. If I don’t want people judging me that I don’t want to diet, I can’t turn around and tell them they’re doing a bad thing by dieting. However, I do think they ought to understand that what they’re doing might not have all of the health benefits they think it will. Informed action, as it were.

  6. Heh. Used the wrong email address there, but you know it’s me. :)

  7. Also, have you been following Greta Christina lately? She’s dealing with some of the same issues.

  8. But how do you know even that’s the reason? What if they just have a lower herditary risk factor?

    Thank you for this. I carry a BRCA1 mutation, which is fairly rare (I think around 1 in 500 to 1 in 800 in the general population), but definitely more common among certain ethnic groups (e.g. Ashkenazi Jews). What this means is that no matter how well I eat, no matter my exercise patterns, no matter how fat or thin I am, I probably am going to get breast cancer someday. I may be able to alter this risk slightly with activity and environmental factors, but the ONLY thing that would significantly decrease my risk would be to have a prophylactic double mastectomy. While BRCA gene defects are rare enough that they probably wouldn’t have a major impact on overall levels of breast cancer in the population, there have been more studies lately showing that there are several other genetic mutations that, while not conferring the 65-87% risk for someone with a BRCA mutation, confer a significantly higher risk of breast cancer than exists in the normal population. These mutations are much more common than BRCA, and probably occur more commonly among specific groups of people. The science of hereditary cancer is in its infancy, and there’s a helluva lot more out there to learn.

  9. That was really kind of tangental, and a reply to a comment rather than the post, but I do want to say “right on!” regarding your post. :-)

  10. I’m not sure how tangential it is, actually. at least, not in a big picture way. I think that there have been wonderful successes in using modern medicine to lower disease rates and improve quality and length of life. And it’s also good to learn what behaviors and environmental factors are harmful and which are beneficial. But sometimes it’s not clear-cut, and it quickly combines with this social obsession with controlling our lives and fixing every little thing in order to prevent any calamity or pain. And a lot of those things probably can’t be “fixed.” And when the efforts to control our bodies and lives, and illness in general, become tied to morality in people’s heads, being sick becomes your fault for not doing it right.

    If you’re sick and you’re at least making the right efforts and they aren’t working, that seems to absolve you of the guilt, but that’s backwards, because it shouldn’t be about the effort. There shouldn’t be blaming associated with health at all. Health isn’t a virtue.

  11. It is still confoundedly questionable as to what is the best way to improve one’s health. I loosely believe that being active promotes blood circulation, and eating the right foods does the same. Therefore, I guess it all comes down to protecting your blood and liver from toxins and waste. If sweating helps with that, and drinking water does, then it is probably good for you.

    Weight loss is not necessarily done just for health, but for vanity a lot of the time.

  12. Pretty pseudoscientific there, lahgibbs. But sure, we don’t have a good idea about the best way to improve health, in part because it’s different for everyone.

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