Women's pre-occupation with weight and shape can have a major impact on their quality of life, according to researchers at James Cook University's School of Medicine.

Senior Research Scientist Dr Jonathan Mond said that the prevalence of both eating-disordered behaviour and obesity has increased substantially in Australia during the past decade.

"There are conspicuous links between eating-disordered behaviour and obesity," Dr Mond said. "Obesity is a potent risk factor for eating-disordered behaviour and individuals with eating disorders are at a greatly increased risk of obesity.

"But while the health risks of obesity have received much attention, the costs of eating-disordered behaviour in terms of mental health and quality of life have received too little," Dr Mond said.

Dr Mond, along with colleagues at James Cook University in Townsville, the Australian National University in Canberra and LaTrobe University in Melbourne, conducted a series of studies to examine the relationship between eating-disordered behaviour, obesity and quality of life.

"Our findings suggest that women's pre-occupation with weight or shape, when taken to an extreme, has a marked impact on quality of life," Dr Mond said.

Moreover, women's levels of weight or shape concerns were found to mediate the effect of obesity on quality of life.

"Overweight women with extreme weight or shape concerns tend to have a very poor quality of life," Dr Mond said, "whereas obesity in the absence of eating disordered behaviour does not appear to be associated with poor quality of life."

The presence of extreme weight or shape concerns, or, to use the language of the Diagnostic and Statistical Manual of Mental Disorders, "an undue influence of weight or shape on self-evaluation," is the core feature that is common to all eating disorders, Dr Mond explained.

"To have an eating disorder, there needs to be this 'cognitive' component as well as one or more eating disorder behaviours, such as binge eating and/or the use of extreme weight-control behaviours, including not only self-induced vomiting and misuse of laxatives or diuretics, but also diet pills, extreme dietary restriction and excessive exercise.

"If there are extreme weight or shape concerns but no regular eating disorder behaviours, then technically there is no eating disorder, although there is a good chance that there will be a problem down the line, or that there has been one in past.

"Our findings suggest that the medical and psycho-social consequences of obesity may have been overstated somewhat at the expense of recognising the public health burden of eating-disordered behaviour in terms of reduced quality of life and increased use of health services.

"It is true," Dr Mond said, "that severe obesity has severe medical consequences, but for the average person who is overweight, without being severely obese, weight and shape concerns and associated eating disorder behaviours affect quality of life far more than being overweight per se.

"Regrettably, eating disorders have not been recognized as a public health problem in Australia and have therefore been given short shrift by funding bodies here," Dr Mond said.

"There is a pervasive misconception, even among some mental health specialists, that eating disorders are either serious, but uncommon, or common but not serious or 'real' mental disorders and/or that they are largely self-inflicted. The reality is that eating disorders are both common and serious."

The studies will be published in a number of Scientific Journals, including The International Journal of Eating Disorders, The International Journal of Obesity, Obesity Research and Behaviour Research and Therapy.