The study of 314 girls from several schools comes as researchers said that most anorexic girls have an inherited brain disorder that pre-programmes them to starve themselves.
In the schools study, Robert Phillips from St Luke's Hospital, Huddersfield and Andrew Hill from Leeds University asked the children, all aged about 10, to pick the three girls with whom they would most like to socialise, and the three most attractive girls in their class.
The girls on restrictive diets were significantly less popular and also seen as less attractive than others who were less concerned about what they ate. Ironically, girls on diets were also heavier and more dissatisfied with their weight and physical appearance than other girls.
The researchers say in their paper: "These findings highlight the social isolation of some girls who tend to be heavier than their peers, have low self-esteem, and are weight-concerned and dieting.
"Peer influences are both important and amenable to investigation," they added. "Further research is needed that examines how peer groups pressure and protect girls' attempts at weight control, at different ages and over time."
The paper will be given today at an international conference on eating disorders organised by Great Ormond Street children's hospital in London and the British Journal of Hospital Medicine.
Another paper to be given at the same conference reveals that most anorexia sufferers had reduced blood flow in an area of the brain governing appetite and visual perception.
Dr Bryan Lask, a consultant psychiatrist at Great Ormond Street, said if the abnormality affected visual perception, this could explain why anorexia sufferers think they are fat when they are dangerously thin.
The researchers carried out brain scans of 19 children and teenagers with anorexia aged eight to 16. Those with the abnormality had significantly less blood flow in one temporal lobe than the other when the flow should be equal in both.
The researchers stressed, however, that psychological and social factors also played a part in who developed anorexia.
"This is an exciting discovery, but it's only a small piece of a large jigsaw. It does suggest that these children have a neurological predisposition in terms of developing an eating disorder." said Dr Lask.Reuse content