Researchers have realized that obesity may be socially contagious and suggest staying around thin if you want to keep thin as obesity as well as thinness tends to among people within the same social group.
Similar effects have been seen among families, but they were not as great as among friends.

A study done among 12, 000 people showed that the chances of becoming obese rose 57% if a person had a friend who was obese but it rose only 40% if they had an obese sibling and 37 % if their partner was obese. The study also revealed that people of the same sex had more influence on each other than people of the opposite sex.

What seems to be happening is that someone gets bigger, they may change norms of what is appropriate weight and body size. If people around you are bigger, you may get the idea that being bigger is ok. We tend to look at others when deciding what and how much to eat, exercise and weigh.

Researchers point out that although there have been so many efforts to find genes affecting weight and obesity, social factor needs to be included as well.

If we would put our mind to helping someone lose or control their weight, it would influence us as well as many around us to control our own eating habits and sizes.