This isn't surprising, given that it's normal adolescent behavior for kids to choose friends based on life aspects they hold in common.

For teens, being overweight may beget having overweight friends, according to a new study.

Researchers from the Keck School of Medicine at the University of Southern California conducted surveys among 617 students age11 to 13 in four schools around Los Angeles. About two-thirds of the participants were girls, and most were in the seventh grade. After height and weight measurements were taken, the students' body mass index scores were calculated.

Being overweight was linked to various factors, including being more likely to have overweight friends than other students who were of normal weight. Overweight girls were more apt to name more friends their normal-weight peers, but were also slightly less likely to be named as a friend.

In the study, the authors wrote, "These results have two important implications: the social contagion of obesity may start at a young age, and social affiliations by obesity status may have far-ranging consequences for adolescent development." The study is published in the August issue of the Journal of Adolescent Health.

Source: Los Angeles Times
http://latimesblogs.latimes.com/booster_shots/2009/07/teens-overweight-friends.html