Are Your Friends Making You Fat?

A new study published in suggests that your friends have a strong influence on your body-weight.

The researcher found that “students were more likely to gain weight if they had friends who were heavier than they were. Conversely, students were more likely to get trimmer — or gain weight at a slower pace — if their friends were leaner than they were”.

And while these observations aren’t exactly new, this study was “designed to determine the reason why obesity and related behaviors cluster in social networks”.

• Is it because behaviors are contagious? – the social influence hypothesis
• Is it because fit students have fit friends and fat students have fat friends? – the homophily hypothesis

Using statistical analysis, the researchers crunched the data obtained from two studies of over 1700 high school students and determined that “part of the reason why obesity clusters in social networks (aka friends) was indeed due to the way students selected friends” – jocks hang out with jocks, etc…

However, they also found that this effect was not entirely responsible for the link between obesity and a student’s circle of friends.