A charity has expressed concern that many adults are unable to name any signs or symptoms of eating disorders other than weight loss or being thin.
Beat said it is important that people recognise the early signs of eating disorders and understand they occur across the weight spectrum, with many people remaining at a normal weight or even gaining weight.
For those who do lose weight, it is only a physical sign that appears once the mental illness is ingrained, it added.
The charity warned that lack of awareness of the early signs of an eating disorder can lead to delayed treatment and increased risk of the illness becoming more severe.
Other indicators include excessive exercise, hoarding or hiding food, hair loss, constipation, fatigue and rapid changes of mood, the charity said.
Beat is calling on the Government and NHS to extend their focus on early intervention and support measures, to increase awareness of the early signs and symptoms.
It commissioned a poll which found that more than a third (34%) of adults were unable to name any signs or symptoms at all.
The survey, which questioned more than 2,000 adults in the UK, also found that of those who gave a correct answer, three out of five (62%) gave weight loss or being thin as a sign over any other.
Beat said a lack of awareness about the complex mental health issues surrounding eating disorders was further highlighted by the fact that, on average, those who gave a correct answer could only list three signs and symptoms out of a potential 68 it has identified.
And four out of five (79%) were not able to name any psychological symptom such as low confidence and self-esteem or a distorted perception of weight or body shape, which usually appear first.
Beat chief executive Andrew Radford said: "This research has showed us that in the UK many people still do not know how to identify an eating disorder in its early stages.
"These results are worrying because we know lack of awareness can stop sufferers getting the treatment they desperately need as soon as possible.
"Eating disorders are serious mental illnesses and when people are treated quickly after falling ill, they are much more likely to have a fast and sustained recovery.
"Today, we are asking that the Government and NHS invest in measures to increase awareness of the early signs and symptoms, heightened awareness will not only improve outcomes for those suffering but also prove cost effective for the services treating patients."
The findings are being released to mark the beginning of Eating Disorders Awareness Week (EDAW).
The charity said when Rachel, 18, started developing an eating disorder nobody suspected it.
She said: "Friends, teachers and my parents all missed the signs. They simply thought I was stressed about my GCSEs leading to my increased isolation, depression and weight loss.
"Even once I was diagnosed my parents questioned it and my mum always says she wishes she would have known what to look for."
She added that delays in recognising her symptoms affected her recovery and she would now be more able to spot the signs of eating disorders.
"I know eating disorders are not just about weight loss but also symptoms such as fatigue, avoiding socialising, lack of energy and rapid changes of mood," she said.