After quitting ballet, Demi went vegan - but insists she now has a healthy relationship with food.
She said: “I don’t know what weight I am now, as I don’t weigh myself any more.”
Demi, who lives with her mum, now works as a make-up artist and produces YouTube videos.
She added: “Anorexia is such an all-consuming disorder, it doesn’t matter how concerned the people you love are, you can’t get better until you want to yourself.
“When it clicked for me that I was wasting my life, I finally wanted to change.
“Now I am in such a happy and healthy place and I hope that my story can show other people going through this that there is hope.”
In related news, new Love Island contestant Kendall Rae-Knight has claimed she was pressured into having cosmetic surgery before entering the villa.
While this mum spends more than ?13,000 on pageants, dresses and make-up to turn her shy daughter into a beauty queen.