The number of patients in England with eating disorders being treated under section has risen at an "alarming rate" in the last five years, new research suggests.
The study found that 86% of eating disorder units in England have witnessed a rise in the number of patients treated under section since 2008.
On a national scale, the number of sectioned patients on eating disorder units has risen by 222% in the past seven years.
According to the NHS, doctors will provide someone with compulsory treatment under section "as a last resort" if they have refused treatment even though they are severely ill and their life is at risk.
Eating disorders charity Beat has said it is "greatly concerned" that one in five patients admitted to hospital treatment for an eating disorder are being treated under section.
For the study, led by Dr Richard Sly at the University of East Anglia, 51 specialist NHS Mental Health Trusts in England were contacted about their eating disorder patient admissions.
A total of 86% of those with specialist units reported sectioning more patients in 2014 than 2008.
More than half (54%) of all patients in one major national unit were treated under section in 2014 – a rise from 4% in 2008.
Beat’s chief operating officer Lorna Garner commented: "The evidence from this research should be ringing alarm bells – more people are getting to a point where their lives are considered at risk or that community care is ineffective.
"Eating disorders are serious mental illnesses and those diagnosed need specialist treatment at the earliest possible opportunity and for the right length of time.
"These statistics demonstrate that patients are either being discharged too early from their first episode of treatment, or that they are not being given the treatment they need early enough."
Garner added that the government has committed to spending £150 million in the next five years to reduce hospital waiting times to just four weeks for young people, but eating disorders affect all ages.
"It is just as imperative that this applies to adults too," she said. "We call upon the government to ensure that people get the care they need no matter what their age is, developing clear admission guidelines for patients who are deteriorating or have risk of relapse to make sure that the care is available at the right time.
"It is appalling that in the UK in 2015 we create the conditions that mean someone has to undergo such horrible interventions when the means to prevent it are well within our ability."
A 23-year-old from the West Midlands, who has experienced what it's like to be treated under section for an eating disorder, has said it is difficult for staff as well as patients.
"I expect the medical team hated force feeding me as I used to get very worked up and aggressive and found it very traumatic" they commented.
Dr Sly has also raised concerns that delaying treatment until a person needs to be sectioned may have a detrimental effect on that individual's health.
"If patients are not provided with the appropriate level of care, at a time when they need it, anorexia nervosa can be a life threatening illness – indeed, the mortality rates for those with anorexia surpass those of any other mental illness," he said.
"Being treated under section in essence is individuals being treated against their will. This can mean that at times, when deemed necessary by the clinical team, these patients may be forcibly tube fed by staff which can be traumatic for all involved – patients and staff alike and it can often have the reverse effect strengthening food avoidance.
"Nurses who carry out these interventions have spoken about feeling highly distressed and burnt out as a result.
"For patients this is an additional trauma to endure as it is for their families and friends who bear witness to the impact of these events."
"For healthcare trusts, these more intensive treatment interventions require more financial resources, the irony being that patients were most likely left to deteriorate in the community because of a lack of financial resources in the first place."
Following the study, Beat is calling for clear guidelines for the restraint of people with eating disorders.
They said: "The current lack leaves professionals exposed to situations where they are expected to restrain and force feed a severely underweight patient with a weak heart and brittle bones."