OBESE boys suffer more distress about their weight than obese girls, according to researchers.

The authors of a study conducted in Australia say excess weight among teenagers appears to be associated with decreased life satisfaction.

However, the researchers have been surprised to find "negative psycho-social impacts of obesity were greater on teenage boys than upon teenage girls".

"Girls in this study who were either overweight or obese did not have significantly different quality of life scores compared to normal-weight girls," lead author of the study Dr Bamini Gopinath said on Wednesday.

Dr Gopinath, a senior research fellow at Sydney's Westmead Millennium Institute, said the reasons for the difference were unknown, but she speculated it might be because of the importance of sport to boys.

"If obesity is limiting their participation in sport, it might negatively affect their social functioning and/or physical functioning, both of which are measured as part of the total score."

The study, published on Wednesday in the American Journal of Adolescent Health, involved 1688 teenage schoolchildren attending 21 randomly chosen Sydney schools.

The researchers found the quality of life score improved for previously overweight boys and girls who lost weight to fit into the normal weight range.

"The findings suggest that an unhealthy weight status and excess body fat could negatively impact on the mental and physical wellbeing of adolescents, particularly boys," said Dr Gopinath.