Health workers are being urged to closely monitor adolescents who are shedding kilos, regardless of their size, after an Australian study found a third of hospitalised teens with life-threatening anorexia were not underweight.

Published in the Journal of Adolescent Health earlier in December, the study busts the common stereotype that only visible, severely thin people could be suffering from the eating disorder.

“You can have a very serious, life-threatening eating disorder and still be within the healthy weight range, or even above it,” lead study author and dietitian Melissa Whitelaw said.

Study findings

The researchers from University of Melbourne and the Royal Children’s Hospital Melbourne worked with 171 adolescents (aged 12 to 19) over nine years between 2005 and 2013, who were admitted to hospital for the first time with a restrictive eating disorder.

About 30 per cent of the participants had “atypical anorexia nervosa”, which means they met all the diagnostic criteria for anorexia nervosa apart from being extremely underweight.

Mrs Whitelaw, a PhD candidate at the University of Melbourne, told The New Daily atypical patients experienced some of the same life-threatening complications usually associated with anorexia.

Low pulse rate, low systolic blood pressure and low phosphate (an essential electrolyte) levels were among the reported health problems.

According to the researchers, atypical anorexia nervosa patients could enter “starvation mode” if as little as 10 per cent of weight was lost quickly, causing the heart rate to slow to preserve energy.

“One of the biggest concerns with the weight loss is extremely low heart rate, which was the primary reason for hospitalisation. We’d describe them as medically unstable,” she said.

“Low heart rate is predicted by weight loss and has nothing to do with body weight at all.”

Psychological changes are also common in people with ‘atypical’ anorexia.

“They might have a fear of weight gain, or feeling that they’re fat, which is characteristic of anorexia,” Mrs Whitelaw said.

The changing face of anorexia nervosa

InsideOut Institute For Eating Disorders director and clinical psychologist Dr Sarah Maguire said anorexia risk presented with every shape and size.

“I’m not at all surprised by the findings. Anorexia nervosa has presented for a long time in people who don’t look emaciated,” she said.

“It’s actually the size of the weight loss that determines a person’s risk, rather than the end point of weight.

“We see this in adults in the healthy weight or above healthy weight range as well.”

Dr Maguire said while this risk was well known and accepted by eating disorder experts, more awareness was needed among the broader medical community.

“It’s so important that GPs understand all the markers of determining a person’s risk for anorexia nervosa. It’s also essential in the hospital setting,” she said.

Balancing healthy weight messages

Mrs Whitelaw said the face of eating disorders is changing against a backdrop of increasing obesity in the country.

“We also have an obesity problem, and we need to address that,” she said.

“I’m not saying [overweight or obese] adolescents shouldn’t lose weight, sometimes it’s a good thing. But it needs to be medically monitored.

“If you give an adolescent the message to lose weight but not follow them up, it can spiral into an eating disorder.”

The experts agreed any weight-loss advice, especially during a person’s teenage years, needed to be approached with caution.

“If parents are told by their family doctor or other medical professional that their child should lose weight, they should approach that very carefully,” Dr Maguire said.

She recommended parents seek expert advice on nutrition from a dietitian or other health professional who has experience with all areas across the weight spectrum.

“In broad terms, it is always better to make healthy food changes as a family rather than have the child go on a diet, particularly diets that lead to significant weight loss over time,” Dr Maguire said.

For support, contact the Butterfly Foundation Helpline on 1800 334 673 or Kids Helpline on 1800 55 1800