Can being obsessed with eating healthy be a mental illness?
The deluge of nutritional and health advice on the internet and in the media could be fuelling a dangerous but as yet unrecognised eating disorder called orthorexia.
Orthorexia nervosa, a term coined in 1997 by Dr Steven Bratman, is a fixation with healthy eating, to the point where it becomes a crippling compulsion, described as "a disease disguised as a virtue".
It differs from eating disorders like anorexia and bulimia in that the goal is not usually to become thin. In fact, ironically, sufferers are initially motivated by a desire to be well, and to consume pure, "clean" foods, often to recover from illness.
One high-profile sufferer is Jordan Younger, who became a poster girl for health with her New York food blog.
The Blonde Vegan had become a successful brand, spawning an app and even a clothing line featuring slogans such as "Oh Kale Yes!" A fervent believer in "clean eating", Younger shared her advice on detoxing and juicing (she would regularly embark on 10-day cleanses) with her 100,000-plus Instagram followers.
Despite seemingly glowing with health, Younger was struggling.
Her lethargy increased and her periods stopped. She also began to be anxious about her routine, panicking when faced with eating a meal she hadn't planned, or something that didn't fit in with her rules.
Younger gradually began to realise that there was something distinctly unhealthy about her restrictive diet.
"I had developed many fears surrounding food," Younger told The Independent.
"I was becoming more and more limited in what I was comfortable eating. I even joked about it with friends, calling certain foods, like eggs, 'fear foods' because I had stayed away from them for so long.
It was easy to hide behind the shield of veganism when I was at a restaurant with friends or even grocery shopping for myself. Anything not clean, oil-free, sugar-free, gluten-free and plant-based I dismissed because it wasn't within my dietary label."
One of the problems with orthorexia is that in some ways it is more socially acceptable than other disorders.
Stand in any gym locker room and you can overhear a woman admit she allowed herself a piece of fruit that day, or a man bemoan messing up his macros. Instagram has 26 million posts with the #eatclean hashtag (with the implication that anything outside of this is dirty), and food diary apps allow you to micromanage your food intake with no lower calorie limit.
The condition is easy to dismiss as the ultimate "first-world problem", and it is not yet classified by the industry standard Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
Younger eventually began a long process of therapy and shifting to a more balanced way of eating, reintroducing eggs, fish and organic chicken, and renaming her brand
The Balanced Blonde. It was no easy transition, as she faced a huge backlash and even death threats from some of her fans.
While a diet focussed on natural foods is far from a bad thing, it is when this becomes so obsessive that it can be damaging to health. Some sufferers begin by cutting out a food group, such as grains or animal products, but can eventually end up on a diet so restrictive, containing such a limited number of 'safe foods', that they become malnourished.
Carrie Armstrong, a TV presenter from Newcastle, became orthorexic after a bout of illness that had left her unable to walk. The doctors had told her that in time she would recover, but Armstrong wanted to do everything she could to move things along. "The only thing I could control was what I put in my mouth," she says.
"You get a physical high from restriction - I was craving purity. I cut out meat, then dairy. I went vegan, but I wasn't seeing the miraculous results I'd expected. I switched to a raw food diet, then just fruit.
By the end I was only eating organic melon. I was six stone, my teeth were crumbling and my hair was falling out"
Armstrong maintains that orthorexia is less about control and more about being "safe". "I didn't control food, food controlled me," she says. "Imagine being terrified of food - it consumed me for eight years."
"Orthorexia is not actually categorised as an eating disorder so we can't say if cases are on the rise but we do seem to hear more about it nowadays - undoubtedly in some way influenced by the huge focus on healthy diet and lifestyle," says Mary George, of the eating disorder charity Beat.
"Orthorexia can bear more resemblance to obsessive compulsive disorder in that it is characterised by a fixation on righteous eating, eating only "pure" foods and trying to avoid contamination by food."
Blogger Ella Woodward's book Deliciously Ella has sold 200,000 copies, making it the fastest-selling debut cookbook of all time. Woodward adopted her vegan healthy eating plan, which is free from meat, dairy, gluten, refined sugar and processed foods, after being diagnosed with a chronic illness.
Tess Ward's The Naked Diet, published this year, is divided into chapters named Pure, Raw, Stripped, Bare, Undressed, Clean and Detox, and claims to offer a stripped back approach to food to help you cleanse your body. The one thing they have in common is restriction, sometimes cutting out entire food groups.
Armstrong points out that most health bloggers or diet gurus are in no way advocating orthorexia. "For people like this, their lifestyle has made their world bigger, not smaller. They are enjoying a discourse with others about food and health. Orthorexia is isolating and lonely."
Some restrictive diets can be healthy, and even necessary, for medical, ethical or religious reasons. Dr Bratman, who not only coined the term but was the first diagnosed sufferer of orthorexia, says the danger is when it tips into obsession. "Eventually orthorexia reaches a point at which the orthorexic devotes much of her life to planning, purchasing, preparing and eating meals," he writes in Health Food Junkies.
Armstrong has previously struggled with alcoholism, and she says she battled both disorders in the same way. "There's no help because it's not recognised. GPs will refer you to a nutritionist, which is a mistake - it should be about taking the emphasis off food. I had to find something to fill my time that loved me back. Food doesn't do that."