Social networks can affect weight, happiness

The people you live with, work with, talk to, email, chatter with on Twitter and Facebook—your social network—can be good medicine, or bad.

The intriguing new science of social networks is demonstrating how personal interconnections can affect our health. Ideas and habits that influence health for better or for worse can spread through social networks in much the same way that germs spread through communities. In social networks, though, transmission can happen even though the people may be hundreds of miles apart.

An article in the December issue of the Harvard Men’s Health Watch explores how social networks can affect weight and mood.

Spreading weight

A study of people taking part in the landmark Framingham Heart Study found that if one sibling became obese during the study, the chance that another sibling would become obese increased by 40%. You could write that off to genetics. The same thing happened if a spouse became obese. Again, no surprise, since spouses share meals and may have similar exercise habits. But if study participants had a friend who became obese, the chance the study participant would become obese rose by 57%. Sure, friends share some meals, but nothing like most meals.

Although scientists don’t fully understand how obesity spreads, they suspect that a social network influences what its members perceive as normal and acceptable. If people see their friends becoming heavier and heavier over time, they may accept weight gain as natural, even inevitable. Instead of exercising more or eating less when their weight begins to creep up, they may simply go with the flow and join the crowd.

Incidentally, there is evidence that the influence of social networks can also work in the other direction, and help people maintain a healthy weight.

Spreading happiness

A different study of the Framingham participants showed that happiness can also spread across social networks.

In the study, happiness spread more readily between members of the same sex than between people of the opposite sex. It also seemed to reach across at least three degrees of separation, spreading, for example, from a friend to the friend of a friend and then to the friend of that friend. But the impact diminished with each degree of separation.

Harnessing the power

The more we know about how healthful habits, positive attitudes, and wise lifestyle choices spread through communities, the more it will help experts use natural social networks to improve public health. As the Harvard Men’s Health Watch article concludes, “This new area of research is worthy of further study, so for now, call it a network in progress.”

You can read the complete article on the Harvard Health website.