Thursday, July 26, 2007

Obesity is "socially contagious"

The media will be all over this one.

A study came out today in the New England Journal of Medicine that showed that over a 30 year period people's weights were strongly influenced by the weights of their friends and spouses.

The study followed over 12,000 folks and mapped their weights against their "social networks".

Their research states:

  • If your spouse becomes obese, your chance of becoming obese rises by 37%

  • If your adult sibling becomes obese, your chance of becoming obese rises by 40%

  • If you're a man and your male friend becomes obese, your chance of becoming obese rises by 100%

  • Don't worry if your neighbours are obese

  • Don't worry if your opposite sexed friend is obese

  • Don't worry if you're a woman and your female friends become obese

    It's actually a beautifully put together study - from the writing, to the methodology, to the gorgeous diagrams and slick video on the New England Journal website that demonstrates the social march of obesity over time.

    So is it important? Does it tell us anything we don't already know?

    I don't think so.

    Friendships and marriages tend to be forged over commonalities, over shared pleasures.

    What am I getting at?

    Marathon running teetotaling vegans are far more likely to be friends with marathon running teetotaling vegans than they are with sedentary, beer swilling carnivores and they're probably alot less likely to marry them too.

    I think what this study proves beautifully is that lifestyle dramatically impacts upon weight and that friends and spouses dramatically impact upon lifestyles.

    So does this study help with prevention and treatment?

    The authors think so,
    "The relevance of social influence also suggests that it may be possible to harness this same force to slow the spread of obesity. Network phenomena might be exploited to spread positive health behaviors"
    I guess what they're getting at is that skinniness may also be socially contagious if harnessed by social networks. Good news is, if the researchers want to, they can simply apply their same statistics and formulae to examine the effects of weight loss in social networks....only problem there is that sustainable weight loss for the most part is a pretty elusive beast.

    Bottom line - your friends and spouses likely share your lifestyle more than your neighbours and coworkers, and your lifestyle obviously has a dramatic effect on your weight.

    What this study should spur you to do is examine how you spend time with your friends and family. If socializing means going out to dinner all the time or hitting the bars, maybe you can suggest trying some less calorie dense, or even some calorie burning activities.

    What this study should not spur you to do is put a sign outside your door that says, "You must be this thin to be my friend".