It’s a typical scene at the conference buffet. People are gathered around the tables loading their plates from heaped bowls of salad, and chicken skewers, vegetables and rice from laden chafing dishes. For dessert, trays of scones flanked by pots of jam and whipped cream are lined up beside the coffee urn. For most of the attendees, this is a happy precursor to an afternoon of presentations.
But for someone with orthorexia – a form of disordered eating – this is a nightmare.
“They probably wouldn’t eat,” says Western Sydney University Professor Phillipa Hay, an eating disorder researcher and psychiatrist. “Or they might, but they would be very selective.”
Someone with orthorexia would be quite anxious about any situation where they were not able to be in control of exactly what they were eating, Hay said at last year’s conference of the Australian & New Zealand Academy for Eating Disorders in Auckland.
Orthorexia nervosa (ON) is an eating disorder on the fringes. It is not included in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (DSM-5), the manual used to diagnose psychological disorders. It is, however, widely recognised by eating disorder specialists amid a growing consensus that it is likely a distinct feeding or eating disorder in its own right.
Hay was one of a group of authors of a 2022 consensus document on the definition and diagnostic criteria for orthorexia nervosa, and she believes it will get its own designation in the future. There’s talk it will be included in DSM-6 in the next few years.

The way orthorexia is usually described is as a preoccupation or obsession with healthy, correct or “clean” eating ‒ consuming foods that are as close as possible to their natural state. Sufferers will often obsess about the benefits of healthy foods and food quality, will self-impose rigid and inflexible rules around eating and might spend excessive amounts of time planning, obtaining and preparing their food. They may also choose to theme their social media posts so the focus is all things food.
There’s a blurry line between people who are interested in and focused on following a healthy eating pattern, and those with ON. But one distinction is that the condition – rather than increasing wellbeing – ends up have a negative impact on sufferers’ lives.
The term “orthorexia” was coined around 1997, but social media has fanned the fire. It can lead to increased anxiety, depression, and social isolation, as well as malnutrition, severe weight loss or other medical problems. Like anorexia, if left untreated, it has the potential to cause organ damage.
“It becomes a disorder because people become so preoccupied with food and eating, that they can’t eat in a relaxed way with other people,” says Hay. “They get anxious, they don’t go out to dinner because of what food might be there, for example.”
One of the questions Hay asks people when she’s screening them for orthorexia is how they’d feel about being exposed to a birthday cake at work. She asks how distressing that situation would be for them. “Would they be able to join in and have a slice of cake, or would they actually find they couldn’t? Maybe they wouldn’t go to work that day because they knew there was going to be this celebration.”
Although it shares many of the features of anorexia nervosa, and the two conditions can co-exist, an important difference between orthorexia and anorexia is the key driver of the disorder: people with orthorexia are not driven by a desire for thinness.
The driver is not body image concern or weight loss. The driver is the desire to have a healthy eating pattern.”
Ideas about what is healthy eating vary widely, depending on dietary trends or a person’s culture and beliefs. The consensus document describes people with ON referring to healthy food as “pure, clean, organic, right, correct, natural or safe” and unhealthy food as “processed, with added ingredients, prepared, treated, toxic or contaminated”.
Eating Disorders Association of New Zealand chair Megan Tombs says there’s no data on the number of orthorexia sufferers, in New Zealand.
However, “Anecdotally, we hear the symptoms of orthorexia nervosa expressed with an anorexia nervosa diagnosis. This could be because orthorexia isn’t yet included in the DSM.”
In Australia, a 2024 investigation found an estimated 4.5% of the population was suffering from an eating disorder of some kind, and this is likely to be similar in New Zealand, she says.
She emphasises these disorders are treatable and people can recover.

Fitness goal
Emily O’Halloran, from Auckland, is familiar with the thinking described in the orthorexia consensus document. Her descent into orthorexia during her second year of university was driven by a fitness goal: to run a half marathon.
“It was very innocent. I felt like I needed to set a goal for myself and I really wanted to keep myself accountable and be on a training plan and do all the stuff that comes with training for a marathon.”
O’Halloran says as a “type A” personality, she immediately started intensively researching how to be a good runner, “which very quickly led me down the road of what to eat to be a good runner. And I took it very logically … do eat this, don’t eat that. I became quite obsessive over those rules.”
It wasn’t long before things escalated. “I guess, in becoming obsessed with the training and making sure I was eating right, unfortunately, that also took me down a path – predominantly on YouTube, but also across Instagram – of veganism.”
Any restrictive diet ‒ even veganism ‒ can be a gateway for some into eating disorders.
“I told everybody that it was an ethical decision [not to eat meat],” O’Halloran remembers. “But if I’m honest with myself, it wasn’t about that really at all.”
The orthorexia accelerated for O’Halloran to include more and more rules and restrictions, which led to weight loss and, for her, a progression into anorexia. O’Halloran says she’d never had any food issues before, but the illness took hold “very, very quickly”.
“I was weighing myself every morning and every night and logging every single thing I ate, down to chewing gum. It was all-consuming.”
Her illness progressed to the point where she was underweight, anaemic and struggled to stand up without feeling dizzy.
Another gateway to orthorexia is the search to cure a health issue. Katie (not her real name), went “down the rabbit hole”, as she describes it, seeking a solution for recurrent candida infections in her 40s.
After repeated medical treatments failed, she looked to alternative options, including diets promoted in popular books. The messages she found made her feel scared, she says.
“I think it really quite frightened me what was happening to my body … just the thought that there was something in my body that was responding to food, and that I could control it in some way by what I put in my mouth.”
The books talked about cutting out sources of sugar. “So that was processed sugar, that was a lot of processed foods. I started following that, and running alongside it was this natural anxiety that I have … I became really obsessed about eating – everything had to be “clean” food. I didn’t even trust going out and eating at a cafe or a restaurant because I didn’t know exactly what was being put in my meals.”
Her self-imposed restriction became more severe and extended to her family. “Like most teenagers, my kids just love fast food. But I was a mum who didn’t really allow them to have that kind of food. I was labelled the food police, and [I was] very judgemental on it, too.”
“If we went out to eat with family, I was the one who always took my pre-prepared food and didn’t eat what everyone else was eating. I was the one who was measuring all my food and things like that.”
When her eating restrictions didn’t improve her health, Katie sought help from a naturopath. It didn’t go well. “That just fed my obsession because [as a result] there were other foods that I became obsessed about that I had to avoid.”
Eventually Katie started binge eating; fuelled, she believes, by her severe restriction.

Algorithm feed
Browse social media for 10 minutes or less and it’s possible to see a wide range of orthorexic beliefs expressed, whether it’s by “carnivore” diet proponents eating nothing but steak and butter or “biohackers” gulping down 60 different supplements a day.
Social media is a miasma of disordered eating content, according to Scott Griffiths, a psychology researcher working at the University of Melbourne.
He and his team have researched the behaviour of people with eating disorders on TikTok, and found the app promotes harmful content to the people most vulnerable to it.
“We developed technology so that if you gave us your consent, we could see every TikTok video that’s ever been sent to you since the day you first installed the app, and every single video you’ve ever liked,” he says. “And that allows us to show that the TikTok algorithms of folk with eating disorders are sending them disproportionately more videos around dieting and exercise that intensify eating disorder psychopathology.”
Even when users don’t engage with the content by hitting “like”, they’ll still see more of it.

“For example, if we look at the number of dieting videos that folks with eating disorders like – they ‘like’ more of them than folks who don’t have eating disorders; about 23% more often. But if we look at the likelihood of the algorithm delivering those videos in the first place, the algorithms are over 350% more likely to send those videos [to those people] in the first place.”
This, says Griffiths, is down to the design of social media algorithms, which often goes beyond our basic understanding of them.
Other social platforms are likely similar. O’Halloran remembers spending hours each day on YouTube and Instagram, describing how easy it was to be exposed to more and more damaging orthorexic content.
“I think I got sucked into being exactly like all these people I was following because I thought they had it all figured out. They spoke like they had it all figured out. Like, ‘If you do this, you’ll end up like me, and it’s great.’ But it ruined my life for a few years.”
Griffiths’ research adds to a growing body of evidence pointing to social media as an accelerator of disordered eating, including orthorexia. The more we consume, it seems, the higher the risk of developing disordered eating. Studies have found frequent reading of posts about nutrition on social media, and engagement with health and fitness accounts are associated with a tendency towards orthorexia, and that social media negatively affects body image and self-image, with the risk rising the more we scroll. Young people are particularly vulnerable.

Misleading symptoms
One of the issues that makes orthorexia such a tricky eating disorder is that – like weight loss – eating healthily is often seen as something good; it’s socially acceptable and often encouraged.
“There is that paradox with it, that it is something that can apparently seem to improve your sense of wellbeing, your quality of life,” says Hay. “If you’re sticking to it, you are probably feeling good about that. And there’s a lot of positive affirmation about healthy eating practices in the general population.”
Katie noticed her friends validating her ostensibly healthy eating choices. “If we were going out, I would get praised by other people who would go, ‘Oh, you’ve got such restraint.’ Or I’d be praised because of the way I looked, or ‘Oh, I wish I could do that.’ It reinforced it.”
O’Halloran: “It’s such a grey area, where you feel that you are looking after yourself or training for something or committing to a goal – prioritising your health, essentially. But then it becomes very, very restrictive very quickly.”
It’s sometimes not until the negative effects become visible that orthorexia is noticed.
“We see that with anorexia nervosa as well,” Hay says. “If people aren’t so thin, they get validated for losing weight. And it’s not until they actually become medically unwell or very thin that people start to think this is not a good thing.”
Orthorexia sufferers, too, can have little insight into their own condition.
“I didn’t [see it] for a while … I just felt really proud of myself,” O’Halloran recalls. “The running was going better and I felt, I think, it was my first taste of being an adult. I was meal planning and creating overnight protein oats … and I just felt like I was doing really well. However, that did turn really quickly, and I definitely knew something was wrong. I didn’t want to acknowledge it. It took me a long time to accept it. Mum would tell me I needed help, and I would just get mad at her.”
O’Halloran was able to recover thanks to the swift intervention of her parents and friends, and treatment from a multidisciplinary team. A decade on, she says she’s in a good place but thinks she will always be vulnerable to disordered thinking around eating.
“I think when people say I’m recovered, I’m worried about ever saying something like that. Because I think it’s an ongoing journey, and it takes maintenance. I think I could very easily just slip into bad habits. I still carry it with me every day.”
For support for eating disorders, go to EDANZ: www.ed.org.nz