Researchers are calling for Australians with eating disorders to help in a study to identify the genes that influence risk of developing the illness.

Australians with first-hand experience of eating disorders have been called upon to be part of a genetic investigation that aims to improve treatment and save lives.

The Eating Disorders Genetics Initiative (EDGI) aims to identify the genes that influence a person's risk of developing anorexia nervosa, bulimia nervosa and binge-eating disorder.

Lead investigator and QIMR Berghofer Medical Research Institute Professor Nick Martin is seeking more than 3500 Australians aged 13 and over to volunteer for the study.

Volunteers need to have currently, or at any point in their lives experienced, anorexia nervosa, bulimia nervosa or binge eating disorder.

Prof Martin says decades of studies have confirmed eating disorders run in families due to genetic factors.

DNA from study saliva samples will allow researchers to identify specific genes associated with eating disorders.

"(This) will help us to determine why some people experience eating disorders, and why some people living with eating disorders respond to certain treatments, while others do not," he said in a statement.

Saliva samples will be compared with samples collected for other disorders which could help to understand the conditions which also occur with eating disorders including obsessive-compulsive disorder, depression, anxiety, substance abuse disorders and personality disorders.

InsideOut Institute for Eating Disorders director Dr Sarah Maguire says eating disorders are a serious illness that can cause significant stress and affect the lives of individuals, their families and friends.

She argues eating disorders have for too long been perceived as body image related.

"In reality, however, eating disorders are mental illnesses driven by what is going on in the mind, and involve a complex interplay of environmental and genetic factors," Dr Maguire said in a statement.

Eating disorders have one of the highest mortality rates of any mental illness, she added.

Sydney office manager and opera singer Stephanie, 30, battled with anorexia nervosa for more than half of her life.

"Anorexia nervosa is something that enters so quietly and takes over your entire life. You become really selfish and before you know it, you've given up everything, and you've got nothing to show for it," she said in a statement.

She hopes her contribution to EDGI will help others living with eating disorders and save lives.

To register for the study go to www.edgi.org.au.

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