Doctors treating children with eating disorders should use the body mass index (BMI) method to calculate the expected body weight of a child.
This is the main conclusion from research that was carried out at the University of Chicago, the Harvard School of Public Health and the University of Rochester Medical Center to find the most effective way of ascertaining a suitable weight.
Doctors stated that currently there are no clear guidelines for doctors with adolescent patients.
Study author Daniel Le Grange, professor of psychiatry and director of the Eating Disorders Program at the University of Chicago, said the teams looked at all current methods of calculating expected weights and aimed to produce a "gold standard".
He also said it was important doctors used the term "expectant" as oppose to "ideal", as the latter can create unrealistic body image expectations.
According to Disordered Eating, those in the 14 to 25-year-old age group are most likely to suffer from an eating disorder such as anorexia or bulimia.
Independent advice on private healthcare