Obesity 'contagious', experts say

Having a friend, sibling or spouse who is overweight raises a person's risk of being obese too, US researchers say.

They said data on more than 12,000 people suggested the risk was increased by 57% if a friend was obese, by 40% if a sibling was and 37% if a spouse was.

They argued this showed social factors, such as the body sizes of other people, were important in developing obesity.

Experts said the New England Journal of Medicine study was not conclusive as other hidden factors could be to blame.