At 18 years old, Christie Swadling's biggest concern should be her subject quota at university.

But instead she is battling an ongoing eating disorder and advocating a healthy diet to other young sufferers, The Daily Mail reports.

'Photoshopped adverts of models like Miranda Kerr definitely started off my body image issues because you think that's how you're meant to be,' Christie told Daily Mail Australia.

'I became skinnier than those models and because of my disease, stopped thinking about the models altogether and became obsessed with just losing more and more weight.' 

The social media motivator has had over 630,000 views on her 'Anorexia Nervosa nearly killed me' video on YouTube and has more than 8,000 followers on Instagram, illustrating her arduous journey from anorexia to finally gaining weight and then her changing her relationship with food. 

Christie's struggle began in primary school when she was bullied for being 'chubby' due to her unhealthy diet.

'My family never had a healthy diet, I was always the kid that everyone was jealous of as I had the chocolate, the chips, the McDonald's,' she said.

'I got chubby at a young age and was bigger than all my friends.' 

The teenager from East Gosford, New South Wales, about an hour and half north of Sydney, was mocked for her weight and called names like 'thick' and was constantly told by high school bullies to 'go back to Maccas.'

It was at this time that Christie began to exercise.

Motivated by her healthy, soccer-playing dad, she began to play different sports and found happiness there.

It wasn't until severe dieting began that Christie ran into trouble and she lost the ability to walk and became bed-ridden.

'It became a problem when I lost a lot of weight - 13 kilogram, I realised I was smaller than Miranda and one moment I liked it and then I didn't like it at all.

Her weight dwindled down to nearly 30 kilograms and she lost all energy 

'I was eating next to nothing, maybe two meals less than 300 calories and there was a devil in my head telling me to be skinny constantly.' 

Her family did not notice her internal battle until it began to show physically, prompting her mother to take her to a doctor.

'I ticked some boxes and they said: 'OK, you have an eating disorder', so they gave me some tips and told me to come back in three months,' Christie said.

Christie got steadily worse after her diagnosis and was admitted to hospital where again her condition stabilised and she was released.

It wasn't until she was admitted to hospital for the third time after she collapsed on her 17th birthday that she began to change her thoughts toward food and started eating properly.

Christie now follows the '80 10 10 ' raw food diet and is inspired by social media health motivators like 'Freelee the Banana girl' and Loni Jane. 

She is back to exercising and is keen to improve her strength and flexibility through yoga and pilates whilst documenting her ongoing journey to her followers.

'I've had plenty of young girls tell me that I'm saving their lives,' Christie said on being asked if she believes she is an influence to her hoards of her fans.

'I've helped so many already and I know that if I put my mind to this I could help so many more.'