Ida's problems started in earnest when she started high school.

She went to athletics high school and became increasingly fixated on food and exercise.

- When I look back on my student period, it is with a darkness, she says.

If the eating disorder is allowed to control, more and more foods will be banned.

In the end, the patient eats very one-sidedly, low in calories and too small portions.

Calling yourself a vegetarian can then be a way to hide the eating disorder.

- What happens is that these people remove food from their diet repertoire such as sugar, white flour and meat.

Everything becomes dangerous and the list of what is okay becomes narrower and narrower, says Klara Edlund, psychologist and associate professor.

Seek professional help

For Ida, the turning point was to seek a professional and contact a psychologist.

Only then did she slowly dare to start eating normally and reduce the amount of exercise.

- I was terrified, she says.

Hear Ida talk about her struggle in the video above.

The documentary series "Eating Disorder" consists of three episodes that are released once a week.

Watch it here on SVT Play.