The NHS is "failing" thousands of patients with eating disorders who are being turned away by doctors because their condition is not deemed serious enough, campaigners have claimed.
Fashion magazine Cosmopolitan makes the stark warning as it launches a joint campaign with eating disorder charity BEAT to urge GPs to take the potentially-fatal illness more seriously and widen treatment for it.
The magazine's editor said many vulnerable patients were falling victim to a tick box culture in the NHS, with doctors waiting for a sufferer to show extreme physical malnourishment before they begin treatment.
An estimated 1.6 million people in the UK suffer from eating disorders, but only around half are diagnosed with either anorexia or bulimia while the rest are categorised as having an eating disorder not otherwise specified - known as EDNOS.
Campaigners say this group are often dismissed as simply being "a bit funny about food" and do not receive the care they desperately need, with some people waiting two years for treatment.
Louise Court, editor-in-chief at Cosmopolitan, said: "EDNOS sufferers aren't just being 'a bit funny about food', they are seriously ill.
"The NHS is amazing in so many ways, but at the same time, it's failing so many women and men who desperately need help now, not in a year's time.
"We're therefore urging GPs to move away from the ethos of merely ticking boxes when it comes to assessing eating disorders. It's time to take a stand and help all these thousands of women who are suffering - a lot of them in silence."
Under current NHS guidelines, women must have a body weight at least 15% below the average, suffer from body image distortion and be so sick they don't have periods before they are formally assessed as anorexic.
While to be diagnosed as bulimic patients must have an irresistible craving for food, binge eat and then try to lose weight through diet pills or by being sick - known as "purging" - and weigh well below normal.
But experts say these guidelines are too restrictive and leading doctors to turn away sick patients who do not easily fall into these two categories.
Clare Gerada, former chair of the Council of the Royal College of GPs, warned that Britons struggling with this mental health disorder face a lengthy wait before they receive the NHS treatment.
She said: "With mental health, if you fall outside of the diagnostic label - and lots and lots of people do - you can't get treatment, either until the condition gets worse, or it doesn't get treatment full stop.
"With eating disorders that fall outside these labels of anorexia and bulimia, there are treatments - mostly behavioural treatments - which are well tried and tested and we should have access to.
"But, for any mental health problem, we currently have a 17-week waiting list for cognitive behavioural therapy. You wouldn't have to wait 17 weeks if you had a broken leg.
"We need mental health to be treated the same as physical health, waiting times should be put in place and there needs to be better investment."
Among those who faced a lengthy wait was Emma Morris, 23, a learning support assistant from Hampshire who went to her GP four years ago and was diagnosed with atypical anorexia.
But she had to wait more than a year to receive treatment, by which time her weight had become dangerously low.
She said: "I was put on a waiting list for treatment, but was told priority would go to people whose weight was lower than mine, and that there were only three adult NHS beds for eating disorder sufferers in the whole of Hampshire.
"By the time I received treatment after a year on the waiting list, my weight had plummeted. Without that wait I wouldn't have got as ill as I did. Then, after 10 weeks of outpatient treatment, I was discharged, as someone more ill needed my place.
"I faced another six-month wait to get a place on some relapse prevention sessions, which luckily really helped me. Three years after seeing my GP, I finally recovered - but I think changes have to be made."
She called for greater investment in mental health treatment, more beds for patients and a larger number of community health teams specialising in the condition.
Care and Support Minister Norman Lamb said the Government is bringing in waiting time standards for people suffering from a mental health problem.
This will give mental health patients the same rights to be seen quickly as someone needing a hip replacement.
He said: "We are determined to end the stigma that surrounds mental health problems, including eating disorders.
"It takes incredible courage for someone with an eating disorder to approach their GP, so we want to make sure when they do, their symptoms are recognised and they get help quickly."
The campaign's launch comes after eating disorder charity BEAT warned that an anorexia epidemic is sweeping through to top independent schools.
Eating disorders cost the English economy an estimated £1.26 billion a year in lost working days and treatment costs, according to a report by BEAT.
And the number of hospital admissions for the condition has shot up by 8% in the 12 months until October last year, according to figures from the Health and Social Care Information Centre.
A spokeswoman for BEAT said: "Eating disorders are serious and claim more lives than any other mental illness - one in five of the most seriously affected will die prematurely from the physical consequences or suicide.
"However they are treatable and recovery is possible. Speedy diagnosis and quick, appropriate referrals are needed to give everyone the best chance of a full recovery.
"GPs need to be better informed and up to speed in order to make that vital first step. We are delighted to be working with Cosmopolitan to educate and raise awareness amongst GPs to ensure everyone affected gets the treatment and help they need from their very first visit to their doctor."