Eating disorders are thought to affect more than 1.5 million people in the UK.
They can be men or women at any age but the vast majority are teenage girls.
Conditions like anorexia, bulimia and binge eating disorder are often linked to modern day diet culture - but many eating disorders are associated with mental health issues.
At the start of Mental Health Awareness Week, ITV Cymru Wales has spoken to four young men and women who are all at different stages of their condition.
They are sharing their experiences in the hope of helping others.
21-year-old Mair Elliot was diagnosed with anorexia at 17.
She has a history of mental illness including depression and anxiety, dating back to her childhood.
She still faces many challenges with her eating disorder.
Like Mair, sports journalist Abigail Davies has anorexia.
She has also found strength to speak about her condition, which she recalls dating back as far as primary school.
As many as a quarter of people with eating disorders are thought to be men and boys.
Luke Evans from Aberdare is one of them and has been living with anorexia since he was 15.
Izzy Harries has learned to overcome the physical challenges of her conditions but she still battles to maintain a healthy relationship with food.
If you need any help and advice relating to eating disorders, get in touch with Beat.
See more: Wales This Week: Anorexia and Me