Just over a million people in the UK suffer from illnesses like anorexia and bulimia, although experts predict the true figure is far higher. Sufferers access NHS treatment through their GP, but many find it difficult to take the first step.
Susan Ringwood, chief executive of the Eating Disorders Association, re-named beat from today, said young people in particular could feel isolated.
Today's "celebrity-driven culture" meant eating disorders were often misunderstood and sensationalised, she said. But, she argued, even when people went to their GP, they could be offered inadequate treatment or have their disorder missed altogether.
"People with an eating disorder do actually visit their GP as often as anyone else," she said.
"But the least likely thing for them to say is "Doctor, I think I might have an eating disorder".
"They are in the doctor's surgery, but they are not going to say it. Doctors therefore need to think of it and ask questions that lead them to work out if there's a need for further investigation."
Research among GPs last year revealed that only about 5 per cent were consulting guidance set out by the National Institute for Health and Clinical Excellence (Nice), Ms Ringwood said.
The guidelines include details on diagnosing a disorder and the treatments that should be offered - such as counselling or referral to a specialist centre.
The one thing that would make the most difference was if GPs "raised the index of suspicion", as highlighted in the guidance, Ms Ringwood said. People were also twice as likely to be offered help if the GP was a woman - possibly because of her understanding of eating disorders or because young girls found it easier to talk to a female, she said.
While there were fantastic specialists working in the UK, there needed to be more of them, she added. The charity released a report today on how young people feel about their disorder.
It found that just 17 per cent of the 600 youngsters questioned felt they could talk to a GP or nurse, 1 per cent felt they could talk to their parents, but 92 per cent said there was really nobody to turn to.
One sufferer told researchers that their doctor said they were just going through "a phase". A focus on being thin and the "size zero" debate adds to the pressure on those who suffer disorders, experts believe.
Diane Whiteoak, manager of the private Huntercombe Hospital in Edinburgh, which treats eating disorders, said: "Pressure on young people in particular to achieve a supposed 'perfect figure' is a contributing factor as they see images of ultra-thin models and celebrities as 'normal' and an ideal to aspire to.
"However, removing a pressure or desire to achieve thinness as a way of seeking perfection and control will help to combat the rising numbers of our children being affected by this most serious and life-threatening condition.
"Because of the nature of these illnesses, the true figures for the number of cases of eating disorders in the UK should be considered to be significantly higher.
"Both anorexia nervosa and bulimia nervosa are very secretive conditions and in the majority of cases sufferers will avoid detection and actively resist treatment until they become very unwell and the illness is out of their control."
Ms Ringwood said: "In today's celebrity-driven culture, where people are vilified for gaining weight then stigmatised for losing weight, eating disorders are sensationalised and misunderstood.
"This is having a devastating impact on young people suffering from eating disorders who feel increasingly alienated and isolated and lack confidence to ask people for advice and support."
Anorexia sufferers tend to be younger than bulimics, with some anorexics being as young as seven or eight. But there are around six times as many sufferers of bulimia, which has traditionally affected people in their 20s, although clinics are reporting younger cases.
Around 15 to 20 per cent of anorexics are men while around 40 per cent of bulimics are men.
Beat offers a range of support services, including telephone helplines, text messaging and emails.