Obesity Appears to Spread Through Social Ties

New research shows that obesity is strongly influenced by social ties, to the point that researchers are actually speaking of it in terms of the "person-to-person spread of obesity" and "clusters out to three degrees of separation" (Christakis & Fowler, 2007). In other words, if your friends become obese, you have a 57% chance of also becoming obese. If your adult siblings become obese, your chances of following suit go up by 40%. If your spouse becomes obese, you have a 37% chance of becoming obese as well.

The bad news is that obesity, related to social networks, does seem to be a significant factor in the current epidemic. However, the good news is that, because it is related to social networks, and because the behaviors of social networks can be changed, there is a great deal of hope that positive behavioral interventions, aimed at entire social networks, can help to change the course of obesity in our culture.

What does this mean to you, and what can you do to influence the social network behavioral changes necessary to fight obesity? The first thing you should not do is begin a backlash against those who are obese, as if they are carriers of a disease that has the potential to affect you. All this will accomplish is to polarize the population, resulting in two groups (obese and non-obese) in a stand-off, with no change in the behavior of either group. The negative relationship between smokers and non-smokers is a perfect example of the environment to be avoided. What you can do is be aware that all it takes to change the behavior of an entire social network is for one person to change their behavior. In time, their behavior will spread and the behavior of the entire group will be changed.

Although this may seem to be an overly simplistic solution to a complex problem, it is not a difficult concept to understand. With research showing that obesity can be spread person-to-person, why could healthy behaviors not be spread in the same way? This suggests the necessity of a change in the approach of public health initiatives. Instead of harping on the negative consequences of obesity, public health dollars would be better spent in encouraging the development of healthy behaviors. One healthy person, embedded in every social network, would then have the potential to spread healthy behaviors throughout their entire range of social associations. Obesity is currently causing a huge drain on the resources of public health. Coronary disease and diabetes alone are two of the most expensive chronic diseases affecting Americans in all socioeconomic groups. If the incidence of these diseases can be reduced simply by introducing healthy behaviors into social networks, then we have been provided with an invaluable tool that cannot be ignored.

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