People who have fat friends are more likely to put on some unwanted pounds as compared to people who have leaner friends, new research suggests. Calling it "imitative obesity," an international team including University of Warwick experts suggest fat friends can cause someone to put on weight too.

Researchers analyzed data on 27,000 people from across Europe and found that obesity is more of a sociological phenomenon than a physiological one, as people are subconsciously influenced by the weight of people around them.

The study found that whether someone is satisfied with their own weight depends on how they compare themselves to their peers. The researchers also find that nearly half of European women feel overweight.

Whether the women are happy with their own weight depends upon not just their own body mass index but also upon their body mass index relative to other women of exactly the same age in their country.

However, less than a third of males feel overweight. Men do not worry about being overweight as long as plenty of men around them were also overweight, researchers found.

The researchers presented their results Friday at a National Bureau of Economic Research conference in Cambridge.