At 23, Liza Palmer weighed 28 stone. Pound by painful pound, she lost more than half her bulk. So why did she still think like a fat girl?

Being overweight is quite the dichotomy. At my peak, in my early twenties, I weighed more than 28 stone. I was enormous. And yet the bigger I got, the more and more invisible I was. But I still don't know who was doing the erasing: society or me. I believed myself to be worthless and unlovable, so my behaviour reflected those beliefs. I extricated myself from the daily goings-on of normal society because I felt that if I rejected it before it rejected me, that somehow I could salvage some shred of dignity. But I wonder: did I think like a Fat Girl before I actually was a Fat Girl?

It was during my senior year in high school when I first really started putting on weight. I believe now that I made a choice: am I comfortable being seen as a woman? Am I comfortable with this new-found attention? As I gained weight, I chipped away at my own femininity.

At college, I sat in the cafeteria and ate a processed-food medley by myself. Two girls sat down and said, "You know, that's how you got like that." I learnt to binge in privacy at home.

I dropped out of college after three months and lived at home. I got a job at a hamburger stand, and so began the longest three years of my life. I gained the weight fast and easy. I ate, worked and slept. The well-worn path I followed every day got smaller as I got bigger. By the age of 23, I weighed 28 stone.

I was filled with self-loathing. Once, in a restaurant, I had to force my body into a chair and was horrified to find I was stuck. I disentangled myself from it without anyone noticing, but that fear of public humiliation persists.

I often wonder what turned the tide. I wish I could say there was a moment whenthe planets aligned to shedlight on the prison of my life. But, one day, I realised that instead of being an observer in my life, I wanted to start steering. I had to lose the armour I thought I so desperately needed.

I began going to the gym. In the beginning, it was more about feeling connected to my body. I had detached so wholly mind from body, that these first trips to the gym were emotional roller coasters of exorcisms and hateful thoughts that I couldn't do it and didn't belong there. But, it felt too amazing to stop.

It was the beginning of a journey of plateauing weights, avoiding "carbs", watching portion sizes, drinking tons of water, giving up soda, learning how to play again, giving up dairy, putting dairy back in - always trying to find the right equation. Learning how to see food as nourishment and not comfort was the hardest thing I've ever done. But it worked. After about three years, I took off close to 14 stone.

Still I wasn't happy. I had a hard time taking the last five stone off. I plateaued and grew frustrated. I was interested in a man, and, as we sat talking one night, I shared with him that I had been overweight. He said, "You mean, more so than now?"

I tried a diet that could give me extreme results fast. I starved myself by cutting out all carbs and eating less than 1,000 calories a day. I went to the gym twice a day. All I thought about was food. I took off most of the five stone and for the first time was officially Not Fat.

Drum roll...

I didn't magically meet the man of my dreams. I didn't automatically become Miss Popular. I didn't get a promotion or get treated differently at work. Sure, I was told I had lost weight. And for the first time, I shopped. I bought clothes that had style and not just the correct size. But I was brainwashed. I was great at the jolly sidekick role. I felt comfortable being invisible and it was only when I was put in the spotlight that I realised how contented I was in my velvet cage of fat. I would be hit on by men, but I would think that they were going through me to get to my prettier friend. I was still in love with Fat and what it did for me. I gained back the same five stone almost immediately.

The closer I got to the curtain that would expose the Great Oz of Beauty and Happiness, the more I clung to a past laden with ballast and fear.

I have started to look at this journey of weight loss as a journey to health. Writing my novel, Conversations with the Fat Girl, I have begun an exorcism. By inundating myself with all this Fat Talk, I have begun to rid myself of the need to have it identify me. I've met with a nutritionist and joined a new gym.

I don't want to be a Fat Girl for the rest of my life. And the term Fat Girl has nothing to do with a number on a scale. That's the true myth.

Thinking like a Fat Girl meant I never stopped counting calories or wincing in the mirror. I apologised for myself and begged people for love. I took what I could get and felt lucky to have been offered anything.

This isn't acceptable now. My body is beautiful. It is not at its goal weight. It could be considered as imperfect, especially in LA, my home, where the tyranny of perfection is at epidemic proportions. But we have to take responsibility for our own lives, and stop allowing the world to tell us who we are and what makes us valuable. For me, that point is now.

'Conversations with the Fat Girl' by Liza Palmer is published by Hodder, £6.99