Are your friends making you fat?

That’s the title of a recent article in the New York Times on research showing that the power of friend-influence is so great it even has a significant effect on your health.  The research was done by Nicholas Christakis and James Fowler using data from the long-running Framingham Heart Study and published in July 2007 in the New England Journal of Medicine.  We see implications for social shopping, as well.

Findings from the study cited in the article include:

• When a Framingham resident became obese, his or her friends were 57 percent more likely to become obese, too.
• A Framingham resident was roughly 20 percent more likely to become obese if the friend of a friend became obese — even if the connecting friend didn’t put on a single pound.
• A person’s risk of obesity went up about 10 percent even if a friend of a friend of a friend gained weight.
• A friend taking up smoking increased your chance of lighting up by 36 percent, and if you had a three-degrees-removed friend who started smoking, you were 11 percent more likely to do the same.
• If a person at a small firm stopped smoking, his or her colleagues had a 34 percent better chance of quitting themselves.
• The article also cited, a 2006 Princeton study which found that having babies appears to be contagious: if your sibling has a child, you’re 15 percent more likely to have one yourself in the next two years.

So, if the example of thin friends can make someone thin, and the example of friends quitting smoking can help someone quit, imagine what seeing friends shop at your store does.