She was 'The Blonde Vegan', whose blog and Instagram account detailed her meals and recipes to tens of thousands of followers. 

As someone obsessed with healthy eating, it came as a surprise to Younger when, just over a year into her public journey with veganism, the 23-year-old began to feel tired all the time, suffered skin breakouts and stopped getting her period.

She recently told People magazine she had been diagnosed with orthorexia nervosa, a condition characterised by an overwhelming focus on a limited diet with elaborate rules that can evolve from an obsessive approach to diet, health and well being.

"I was spending the entire day obsessing about eating only vegetables, green juices, fruits and occasionally nuts and grains," said Ms Younger, adding food was no longer enjoyable. "I was following thousands of rules in my head that were making me sick."

The term orthorexia nervosa was coined in 1997 by Californian doctor Steve Bratman in a book titled Health Food Junkies. He defined the condition as a fixation on healthy eating or pure food such as vegetables. The rigid approach to healthy eating usually includes extensive and even punitive exercise regimes.

While the condition isn’t officially recognised by the Diagnostic and Statistical Manual of Mental Disorders, Australia’s peak body for body image illnesses said it conforms to the behaviours that define eating disorders, which affect more than 900,000 Australians.

There are four broad types of eating disorders, including anorexia nervosa, bulimia nervosa and binge eating. According to the Butterfly Foundation, Orthorexia fits into the fourth category: identifiable sets of behaviours that make up a condition not otherwise specified.

Chief executive Christine Morgan told Fairfax Media eating disorders have a genetic predeterminant that is triggered by a nutritional deprivation.

“Nutritional deprivation is one of the key behavioural elements of an eating disorder. This can manifest in many forms, either by excluding whole foods groups or food types and then obsessively managing the consumption of these foods. Other behaviours include excessive exercise, withdrawal from social settings where food is involved, secrecy and covert behaviours.”

Jordan Younger launched The Blonde Vegan in early 2013, accumulating more than 70,000 Instagram followers, sharing photos, tips and recipes.

In a recent blog post explaining why she was transitioning away from veganism - she has since renamed herself The Balanced Blonde - Ms Younger said her online persona had obscured her understanding of what she was going through.

"My blog made it hard for me to see that I had an eating disorder. If I wasn't so closely tied to the vegan identity I'd given myself, I would have realised it a lot sooner," Ms Younger said.

Amanda Benham, a practising nutritionist with a masters in health science, said 

veganism was an ethical position rather than a fad diet.

“It would be a bit of a stretch to blame veganism for an eating disorder,” Ms Benham said. “My guess is she had a predisposition for this, so whether she went on a vegan or a paleo or a low-carb diet, the outcome might have been the same.”

She said that provided vegans followed a few basic principles, they could maintain a healthy diet and life. 

If you are concerned that you or someone close to you is grappling with an eating disorder, seek help. The Butterfly Foundation: 1800 334 673; Lifeline Australia: 13 11 14; Kids Helpline: 1800 551 800.

SMH