Can Social Networks Make Us Fat? A New Harvard Study Says “Yes”!

Weight gain is usually blamed on fast food, genetics and a lack of exercise. However, new research conducted by Harvard and the University of California, San Diego, suggests that obesity is “socially contagious", and that friends are generally a bigger contributor to obesity than genetics.

A study of more than 12,000 people found that having an obese friend more than doubles your own risk of becoming obese (57%). In spite of shared genetics, having an overweight brother or sister only increased the chances by 40 per cent—not much more than the increase associated with having a heavy spouse, which was 37 per cent.

Physician Nicholas Christakis of Harvard Medical School said the findings could not be explained by friends simply eating the same foods or living a similar lifestyle.

"It's not that obese or non-obese people simply find other similar people to hang out with," said Christakis, "Rather, there is a direct, causal relationship."

"When we looked at the effect of distance, we found that your friend who's 500 miles away has just as much impact on your obesity as [one] next door," said James Fowler, an associate professor of political science at UC San Diego and an expert in social networks.

Gender also appears to play a big role in this effect. People with an obese friend of the same sex had a 71 per cent increased risk of becoming obese. However, if a man's brother was heavy, his chances of becoming obese increased by only 44 per cent, while among sisters the risk rose by 67 per cent. Interestingly, among friends and siblings of opposite genders, there was no increased risk found.

"The fact that neighbors don't affect each other and that geographic separation doesn't influence the risk among siblings or friends tells us that environmental factors are not essential here," said Christakis. "What appears to be happening is that a person becoming obese most likely causes a change in norms about what counts as an appropriate body size. People come to think that it is OK to be bigger since those around them are bigger, and this sensibility spreads.”

"It's important to remember," Fowler said, "that we've not only shown that obesity is contagious but that thinness is contagious."

Fowler notes that this research shows that the obesity epidemic is a social problem, and not solely the result of genes or lifestyle.

"This is about people's ideas about their bodies and their health. Consciously or unconsciously, people look to others when they are deciding how much to eat, how much to exercise and how much weight is too much."

Posted by Rebecca Sato

http://www.physorg.com/news104603654.html