Can friends cause you to be overweight?

The circle of friends of an individual could be key when it comes to gaining or losing weight , according to a new scientific study. The research, conducted among high school students, found that teens were more likely to pack on extra pounds if they spent time with friends who weighed more than themselves. However, the opposite was also true for students with slimmer friends.

"The main conclusion is that when we try to prevent obesity, we should not treat adolescents in isolation," explained David Shoham, assistant professor in the department of Preventive Medicine and Epidemiology at Chicago's Loyola University Stritch School of Medicine. (USA).

To conduct the study, the researchers examined information previously collected from students at two large high schools over two school years. One college, known as Jefferson High, was located in a rural area and with a majority of white students. The second center, called Sunshine High, was urban and its student population was both racially and ethnically diverse.

The data showed that a Jefferson High student with skinny friends had a 40 percent chance of losing weight and a 27 percent chance of gaining it. However, the researchers found that a student who was close to overweight and with obese friends had only a 15 percent chance of losing weight, versus a 56 percent chance of gaining weight . Their findings have been published in the journal PLoS ONE .