Your Weight Loss Will Help Me, Too!


Check this out…

In 2007, two researchers, Christakis and Fowler, published an interesting, counter-intuitive study on the link between relationships and weight gain in the New England Journal of Medicine (2007, July 26). They reviewed data, collected over 32 years, from a social network of over 12,000 people.

What they found was that “obesity appears to spread through social ties” (p. 370). OK, so non-athletic people like to hang with, um, non-athletic people? Well, it’s not so simple.

In fact, if I gain weight, and you are my friend, you are 57% more likely to gain weight than if I didn’t. Here’s surprise number one: that effect works even if you are all the way across the country from me. Surprise number two: if you are my sister or my brother you will only be 40% likely to pack on the pounds. And surprise number three: if you are my spouse you will only be 37% more likely to gain weight if I gain it, even though we graze from the same kitchen, shop together, and eat the same meals.

Wow. Really? My weight gain will affect yours, all the way across the country? In fact, it spreads through groups of people like a virus? Zowie.

They even eliminated several influencing factors, one being the idea that clustering according to body size occurs because overweight people befriend other overweight people, and likewise with thin people. They did this by only looking at pre-existing relationships where both people started out at a normal weight, after which one of them gained extra pounds, and then looking at what happened to the other people in their network.

The exciting potential this brings to mind, then, is that if this effect works one way, maybe it will work the other! If I lose weight then maybe it will be easier for my friend to lose weight, too. Even better if the weight loss goes “viral!”

Cool! Two (or three or four!) for the price of one! (Woo hoo! A good virus!) Any friends want to help me out?

Can I help you, too?


NB  – Dr. Christakis’ comment in his video is that “weight gain in my friend might increase my probability of gaining weight by 70%,” whereas in the published article he and Dr. Fowler state that the effect is to increase the likelihood of my gaining weight too by 57%. Either way, it’s a lot!


Christakis, N. A., & Fowler, J. H. (2007). The spread of obesity in a large social network over 32 years. The New England Journal of Medicine, 357(4), 370-379. Retrieved on May 26, 2008, from

Direct Link to Article:

Direct Link to Video:

More Resources: Eat, Drink, and Be Merry: The Spread of Obesity, Nicholas Christakis (1 hour, 10 mins)

NB – All links created October 21, 2008. Hopefully they endure for as long as you need them to! Drop me a note if you run into trouble and I’ll see what I can do.

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