Rake thin, visible ribs, emaciated bodies. The stereotypical ‘look’ of people with anorexia nervosa is well known.
But our research at the Royal Children’s Hospital Melbourne and the University of Melbourne has found that anorexia is actually possible at any weight.
Anorexia’s many guises
We worked with 171 adolescents over a period of nine years between 2005 and 2013, who were hospitalised for the first time with a restrictive eating disorder. Our results are published in the Journal of Adolescent Health.
We found around a third had ‘atypical anorexia nervosa’, where they met all the diagnostic criteria for anorexia nervosa apart from being severely underweight. Over the study period, there was a five-fold increase in hospital admissions for this condition.
These patients still experienced the same life threatening complications usually associated with anorexia, including a low pulse rate, low systolic blood pressure and low phosphate levels.
But they didn’t present with the highly visible, severe emaciation that has long been considered the core diagnostic criterion for anorexia nervosa.
We also found the total and recent weight loss were stronger predictors than weight itself for a number of clinical complications, with the strongest predictor overall total weight loss. A striking finding was that no outcome was independently associated with low admission weight.
In other words, it seems anorexia’s symptoms are associated with weight loss, not necessarily emaciation.
We need to rethink how we conceive restrictive eating disorders; in actual fact, they can emerge at any weight, and adolescents who have lost large amounts of weight should be assessed for a possible eating disorder – no matter their size.
None of the adolescents participating in our study were being monitored by a health professional, despite being advised to lose weight in some cases.
Balancing healthy eating messages
With overweight and obesity a major health issue in Australia, we have seen a proliferation of information about its prevalence and complications throughout society.
Appropriately, healthy eating and lifestyle programs are taught in schools. But elsewhere, adolescents are inundated with messages about dieting, often with inappropriate recommendations for quick fixes promising fast weight loss, advice on how to change body shape and images of ‘beautiful’ thin bodies.
And while adopting a healthier approach or dieting for weight loss can be done in a way that is healthy and safe, for some adolescents it can trigger eating disorder cognitions and lead to them adopting increasingly restrictive diets.
For some, this can become a vicious cycle as they receive positive reinforcement about their weight loss from friends and family. For those with previously higher weights, positive affirmations for their weight loss are common and, in some cases, they are even encouraged to continue losing weight.
We don’t yet know why some adolescents are susceptible to this while others are not, but it isn’t surprising this is the most common age for eating disorders to develop - they are the third most common adolescent chronic illness after obesity and asthma.
Adolescence is a highly dynamic period of development as we acquire the physical, cognitive and emotional characteristics of adults. By the end of adolescence, we are sexually and reproductively developed, our bodies are grown and our brains have matured.
Although adolescence is generally considered a time of robust physical health, it is often the age when mental health disorders emerge. Psychiatric illness is considered common at this age, with 50 per cent of adult mental disorders reported to have started by the age of 14 years.
Body image concerns are also common, as is a heightened susceptibility to dieting. And for some, this can become dangerous.
It’s important to be conscious of how food is discussed around adolescents; stigmatising discussions that relate food to body weight can encourage them to adopt restrictive diets.
It’s much more effective to offer positive healthy eating advice, like eating more fruit and vegetables.
A new way of diagnosing anorexia
In the future, weight loss in higher weight adolescents, even those who have been assessed as overweight or obese, should be closely monitored by health professionals so that if an eating disorder emerges, it can be picked up early.
This should include a review of the patient’s weight loss strategies to ensure they are sustainable and safe, as well as an assessment of their cardiovascular health.
And we need to rethink the diagnostic criteria for anorexia nervosa, the most serious of all eating disorders.
Our findings suggest that weight loss, as well as weight, should be included in future revisions of the diagnostic criteria for anorexia nervosa.
It’s not just about being underweight.
Melissa Whitelaw’s PhD supervisors are Professor Susan Sawyer who leads the Population Health research group at the Murdoch Children’s Research Institute and is Chair of Adolescent Health at the University of Melbourne and Director of the Royal Children’s Hospital Centre for Adolescent Health; Associate Professor Katherine Lee, Senior Biostatistician at the Murdoch Children’s Research Institute; and Dr Heather Gilbertson, Manager, Nutrition and Food Services at the Royal Children’s Hospital.
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