Your friends make you fat

(Subtext: so if any of your mates are a wee bit plump you better drop them quick smart or you’ll be rooned, rooned! Yay, let’s make fat people even more socially isolated and scorned!)

So say all the headlines and radio shows this morning, based on a study in America that has found a correlation between gaining weight and having friends who also gain weight. The talkback shows especially are full of all the talking heads of the Diet Industry sagely shaking their heads and wagging their fingers at the ‘obesity epidemic'[1].

Most of the discussion I’ve heard has focussed on “individuals”, but you know what? The study found that the “friend” correlation only holds up for men.

The researchers found that when a person becomes obese, the chances that a friend will become obese increases by 57 percent. Siblings of obese people have a 40 percent increased risk of obesity, and their spouses’ risk increased by 37 percent.

On average, having an obese friend made a person gain 17 pounds, which put many people over the body mass index (BMI) measure for obesity.

Female friendships did not seem to be impacted by obesity. But the chances that a man might gain weight from having a fat pal doubled for so-called mutual friends — friends who both listed each other as buddies.

I found that the correlation (of course the news reports are calling it a cause, but that’s a whole other rant) being confined to male friendships was only mentioned in one report. Most other reports don’t report that it doesn’t hold for women. [link] [link]

Yet another case of “male” being the default for “human”? Or a case of not wanting to mention that the correlation didn’t hold for women just in case it meant hordes of women thinking that they shouldn’t dump their fat friends right away just to be on the safe side?

There’s a whole lot of other issues to be taken with conclusions being drawn from the study as well.

Christakis and Fowler studied the records of 12,067 people taking part in the Framingham health study, which included most of the residents of the mostly white, middle-class town of Framingham, Massachusetts.

The Framingham longitudinal study started in 1948, and grew to incorporate longitudinal tracking of spouses and offspring over the generations. The friends studied are all people given as ‘alternate contacts’ from original study participants, so they too are overwhelmingly folks with strong historic ties to Framingham, Massachusetts. Thus there must be a multitude of genetic and environmental factors that the bulk of the study population have in common which do not appear to be taken into account by this study, at least not from what is being reported.

As Kate Harding points out, what other researchers have found from examining the data in the Framingham health study does take into account the genetic and environmental commonalities between the study population:

It’s well worth mentioning that that study demonstrated, among other things, that there’s no clear link between longevity and BMI, that among non-smokers, obesity was correlated with greater longevity, and that the largest single determinant of longevity was”¦ drumroll”¦ genes.

Kate also rips this study apart on a number of other levels. Go read.

1. The ‘obesity epidemic’ is largely a moral panic and many of the fat=unhealthy factoids are myths. See Kate Harding’s blog and various other Health At Every Size (HAES) blogs on her blogroll for more information.



Categories: health, skepticism

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8 replies

  1. Even if you buy into the idea of fat being a problem (when actually being obsessed with fat, diet & exercise is a far bigger problem) the conclusion that men tend to have friends who look the same is hardly revolutionary. People generally have friends from the same ethnic background (hello shared genes!), they often work in similar environments (with similar levels of work-related activity), and then they tend to hang out together (because they enjoy each other’s company) so they eat together, and they do activities together (anyone for golf?). So whatever shared genetic tendencies they have are encouraged along by shared diet & exercise regimes.
    Why that doesn’t happen with women is interesting, but I don’t know why it would be. A friend and I got in the habit of refusing to engage in any talk of weight with our friends many years ago. The fact that we felt it necessary to formulate a policy on that is indicative of how much energy women waste thinking and talking about their efforts to ‘perfect’ their bodies.

  2. There’s more cheerful news from a different study:Fitness is less belly fat at any weight

    The higher a man’s cardiorespiratory fitness, the less fat he has in his abdominal cavity, Dr Jean-Pierre Despres of Hopital Laval Research Centre in Quebec and colleagues found. The relationship held true regardless of body mass index (BMI), a ratio of weight to height typically used to gauge overweight and obesity.
    […]
    High waist circumference combined with high triglyceride levels signal a substantially increased risk of heart disease and diabetes, he explained.
    Evidence shows fit people are at reduced risk of heart disease, even though they may be overweight or even obese based on their BMI, Despres and his team note in the Archives of Internal Medicine. At the same time, people of normal weight with bulging bellies risk heart disease.

    I note that the emphasis on how “fat people can too be healthy!” does tend to cast fat people who are unhealthy as outsiders and lesser, and that’s still a problem, because they’re still humans deserving dignity. Maybe if we can demolish some of the most pervasive fat-hating myths though the unhealthy fat people will also be subjected to less fat-hatred.

  3. Heh, I’d noticed the “gaps” in the reporting on this, as well. Yes, media reports on science are always painful, but what’s being left out of this seems more than coincidental.
    On a related note, I have noticed that since I’ve lost weight over the last two years, people almost always comment that both I and the Zombie King have really slimmed down. He’s lost a bit of weight, just because I’m cooking with less calorie-dense foods, and so on, but he’s only lost maybe 3% of his body weight or so, whereas I’ve lost more like 33%. It’s more than just politeness to him, too, as they will often keep remarking on it to me when he’s not around. Not that I care, I love my doughy guy and I didn’t lose weight for anyone but myself, but it’s happened a remarkable number of times.

  4. BMI is pretty unreliable I think. On TJ’s blog some time ago she was talking about BMI and one of the fitness instructors who is a tall, very heavily muscled man with less than 10% body fat, but his BMI puts him the the obese category. I don’t think it adequately allows for bone density either. As a woman with size 14 shoulder bones, hip bones and size 10 feet I don’t think that I should share a BMI with someone of the same height but much slighter build.

  5. BMI is notoriously unreliable. It was developed as a rough and ready reckoner for adiposity in sedentary adults over a century ago. Significant muscle mass confounds BMI totally, as do childhood growth spurts.

  6. Sorry, for clarity this clause should have an added phrase:

    Significant muscle mass confounds BMI totally as an indicator of adiposity.

    Every front row in either code of rugby is technically obese according to the BMI. Of course by other measures of adiposity they have low levels of subcutaneous fat and when their cardiovascular fitness is tested it is superior to most people with a much lower BMI.
    BMI is an arbitrary number which has been elevated into this almost holy signifier of health, just because calculating BMI is easy whereas taking other more rigorous measurements of adiposity and actual fitness take time and money.

  7. Three in a row!
    Yeah, Mindy: bone density and body type (ecto/meso/endomorph) are confounders for BMI reliability as well. I’m only medium height but I’ve always been about 10kg heavier in actuality than what people estimate me to be – I just have heavy bones and dense muscle mass.
    That said, I am currently well overweight and not just according to BMI either, as a result of illness and medication side effects combining to make me sedentary (gradually improving). But if anyone tried to say my fat was making me unhealthy I’d point out that they’ve put the cart before the horse – my ill-health is what made me fat.

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  1. Pandagon :: Having fat friends does not hurt your standing in the patriarchy :: July :: 2007
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