There was a 55% increase in the amount of people who attended eating disorder support services last year.
The new figures have been released by Bodywhys, the Eating Disorders Association of Ireland.
Its e-mail service also grew by 71%, as more and more people sought help with their condition.
Ellen Jennings, from Bodywhys, said there were several reasons for the spike in 2021.
"During the pandemic there was increased uncertainty and a change of routine for people, so that could have intensified things for people.
"We know that it pushed people towards coping in that way, who may have been vulnerable to coping in that way.
"And also people who were already experiencing an eating disorder, or in recovery from an eating disorder, may have experienced a relapse".
She said there was there a particular spike in binge-eating disorders.
"People affected by binge eating disorder can often engage in behaviours in secret, and there's a lot of shame and embarrassment around those behaviours.
"That means that it can go unnoticed for longer, and also it's hard for the person to open up about these types of feelings.
"It's important to remember that an eating disorder is a coping mechanism for dealing with something else in the person's life.
"So really the behaviours are just a symptom of what might really be going on for the person," she added.
Anyone affected by issues raised in this article can contact Bodywhys on (01) 210-7906 or e-mail email@example.com