People May Adopt the Diet and Exercise Patterns of the Least Fit in their Peer Group

August 24, 2013



diet and fitness
Who you follow makes a difference.
The decline in the physical fitness of the U.S. population has been increasingly in the news.
Nearly two-thirds of adults are currently overweight, while more than 30% are obese.
While societal factors have shifted people toward increased food consumption or decreased exercise, a provocative recent explanation is that the effects of social and environmental factors may be amplified by the person-to-person spread of obesity.
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.
This explanation has profound implications, as it suggests that social networks can multiply the effects of otherwise smaller changes in the determinants of obesity.
Conversely, if social networks are an important determinant of health, policies that increase individual health could conceivably combat the obesity epidemic.
So be a good influence!
Sources: and Harvard daily blog