We think of many things as contagious but rarely do we think about weight loss as being contagious.

Yet a new study has demonstrated that weight loss is contagious; that when weight loss interventions are team based, they are more effective.

How weight loss can be contagious

A 12 week online campaign for weight loss that included 3330 overweight people divided into 987 teams was analyzed by academics at the Brown University. Team outcomes were found to be a strong indicator of a person’s personal weight loss. When participants were seen to lose significant amounts of weight (5% or more of their body weight), they were found to be on the same team.

Weight Loss and Obesity

In other words the influence of one’s teammates was seen to be very significant and it increased the chances of losing weight by as much as 20%. The study concluded that harnessing and maximizing the influence of teammates for losing weight could improve outcomes among people looking to lose weight.

So if our social influences can help us lose weight, can the reverse be true as well? Is it possible that the company you keep is preventing you from shedding weight, or that it is causing you to pile on even more pounds?

Obesity is contagious too

If weight loss is socially contagious, obesity is contagious in a similar way and for the same reasons.

A study conducted some years back found that our chances of becoming obese rise by as much as 57% if we have a friend who is on the road to obesity. Similarly, having a spouse of a sister who becomes obese also raises our chance of doing the same.

In this study published by The New England Journal of Medicine, researchers mapped the social networks of the study participants and obesity trends within those networks. It was found that family members and friend circles are connected and so is their health.

And this connection could exist even over geographical distance. People seemed to influence each other’s weight loss and weight gain as well as overall health even when they were physically hundreds of miles apart.

This phenomenon is explained thus: if you see a sibling or a friend once in a year, say for the holidays, you may notice that they’ve put on some weight and you may think it’s OK to let yourself go a little bit as well! And same sex friends and siblings were seen to do the most damage!