Obesity is socially contagious

A new study that looked at data collected over 32 years from the Framingham Heart Study, an ongoing cardiovascular study begun in 1948, found that when an individual became obese, the chance that a friend will become obese increased by 57 % even if they were geographically distant.

Researchers said that obesity spread through social ties (see diagram in the article), particularly close friendship. Some experts said the results suggested that people influence one another's behavior and share the ideas about what an acceptable weight is, so it might be more effective to treat obese people in groups than individuals to slow this worldwide epidemic. Read the press release.

The study "The Spread of Obesity in a Large Social Network over 32 Years" is published in NEJM, July 26, Volume 357:370-379. Free full text.