While obesity during adolescence is a major health concern, an eating disorder expert has warned that obese teenagers who manage to lose weight are at risk of developing eating disorders such as anorexia and bulimia.

According to Dr Leslie Sim of the Mayo Clinic Children's Center in Minnesota in the US, eating disorders among this group are often missed because their weight loss is viewed as positive by their family and healthcare providers.

She noted that formerly overweight and obese teenagers now represent a substantial number of teenagers presenting for treatment for eating disorders.

Dr Sim said that these young people tend to have more complications associated with their eating disorder and it takes longer to diagnose them compared to children who were previously in the normal weight range.

This causes major problems because early intervention is essential in the treatment of these disorders.

"Given research that suggests early intervention promotes best chance of recovery, it is imperative that these children and adolescents' eating disorder symptoms are identified and intervention is offered before the disease progresses," she said.

She added that with eating disorders, there is a high relapse rate ‘and significant impairment to daily life'.

Dr Sim made her comments in the journal, Pediatrics.