Poor Fitness Spreads Through Peer Groups

A study in which college students were assigned to spend most of their time with 30 other randomly chosen undergraduates shows that people may adopt the diet and exercise patterns of the least fit within a peer group, says a team led by Scott E. Carrell of the University of California-Davis. The data suggests that if half of your friends were to become among the least fit (for reasons unrelated to you), your own fitness level would drop by nearly 20% of a standard deviation. The people most susceptible to being influenced by the least fit are those who are already struggling to maintain their fitness, the researchers say.