There were 121 children under the age of 16 hospitalised with anorexia last year.
New figures, released under the Freedom of Information Act, show the condition affects far more girls than boys.
A total of 247 people had inpatient admissions in hospital last year due to either anorexia or bulimia.
In 2020, there were 10 admissions with bulimia and 237 people were admitted with anorexia. Of these, 94% of them were female.
A total of 121 boys and girls under 16 were hospitalised with this disorder - along with 77 aged between 16 and 24.
Dr Martin Daly, a former president of the Irish Medical Organisation, says anorexia is a devastating illness.
The disorder can cause serious physical and psychological harm to the sufferer and Dr Daly says eating disorders are one of the biggest challenge to the medical system at this time.
"At any given time, one out of every seven women is estimated to be struggling with an eating disorder.
"A number of studies have found that up to one-third of adolescent girls believe they are overweight and up to 60% are trying to lose weight."
The HSE says anorexia has the highest death rate of all mental health disorders.
Dr Daly says there are many causes of anorexia including social media.
He said the pursuit of body perfection, often triggered by social media, has contributed to anorexia and eating disorders.
"It is not the only trigger, it is a complex illness and there are many triggers.
"Control being one of them, distorted body image being another and obviously this is taken to an extreme in the case of people who suffer from anorexia."
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