The 19-year-old singer-and-actress - who checked into rehab in October 2010 to receive treatment for self-harm and bulimia- can`t remember ever having a normal relationship with food and has always been plagued with thoughts about being too fat.

She said: "I think I was born with an eating disorder, because I`ve never had a relationship with food that was normal.

"I remember looking in the mirror with nappies on thinking, `You?re fat, change it`.

"II started overeating when I was about eight; I was a binge eater. I would bake a whole plate of cookies and eat them all. Then when I turned 12 I was bullied in school and they called me fat. I went from being an overeater to stopping eating and I lost about 30lb. From then on I continued undereating, but my weight plateaued.

"[Then] I started throwing up to lose weight."

Demi also revealed she started self-harming when she was 12 years old and admits to "self-medicating" with drugs and alcohol.

She added in an interview with You magazine: "I started when I was 12, when I was bullied. It was my way of dealing with the stress and then I often resorted to it when I was feeling overworked.

"Girls [who self-harm] scratch or cut themselves with razor blades, scissors or sharp objects, or burn themselves. I`ve pretty much tried all of it. My main thing was cutting and that was so horrible.

"I definitely self-medicated with drugs and alcohol. I would be lying if I said I didn`t."

Though Demi is now focused on her recovery, she is aware that she will be fighting her problems for the rest of her life.

She added: "There`s definitely temptation - every meal I fight it. It`s an addiction and I`m going to have to fight it for the rest of my life.

"There`s no cure and I may mess up, but I want to be a better role model for my fans and my younger sister."
sections: Celebrities