All too often women with eating disorders cannot recognise they have a problem, or go to great lengths to disguise the problem from others.
This makes the disorder difficult to diagnose and even more difficult to treat.
But now researchers have developed a test which shows by analysing the carbon and nitrogen bound into hair fibres, it can be discovered whether a person has an eating disorder.
A multidisciplinary team of researchers from Brigham Young University (BYU) in Utah, say the test will show whether someone is battling with conditions such as anorexia nervosa and bulimia.
Hair it seems grows by adding new proteins to the base of the strand, and pushes the strand up out of the hair follicle and these proteins are affected by a person's nutrition.
A person's nutritional state is affected by eating patterns associated with eating disorders and because hair grows continuously, each strand consequently becomes a chemical diary of an individual's day-by-day nutrition.
The researchers set out to examine if protein patterns differed between people with eating disorders and others with normal eating behaviours.
They found that by careful statistical analysis of the data, they were able to give an 80% accurate prediction about whether a person had anorexia or bulimia, the two most common eating disorders.
The test was so powerful that it required only five stands of hair.
Lead author Kent Hatch of the university's department of Integrative Biology, says although the test needs refining before it is ready for routine clinical use, they are confident the test has the potential to provide an objective, biological measure for diagnosing eating disorders.
It means doctors will not have to just rely on self-reported information and qualitative interviews with patients.
Data collected this way is often highly subjective and demands honesty from the patient.
According to the U.S. National Institutes of Health, more than 90 percent of people with eating disorders are women between the ages of 12 and 25.
However new research indicates that increasing numbers of older women and men also have the disorders, which without proper treatment, can lead to malnutrition, heart problems and other potentially fatal complications.
The research is published in the current issue of Rapid Communications in Mass Spectrometry.