When I was nine, I was unpopular at school. I didn't have to wonder too long why this was so; my adversaries were keen to point out the reasons. They followed me home from school calling 'four eyes' and 'fattie'. This went on for a few months, until I confessed to my dad. Beat 'em up, he said. So one afternoon I attacked the ringleader, in a sixties version of Girl Power. I was hauled into school and branded as a Juvenile Delinquent, my parents tried to justify my actions, and the taunting mysteriously stopped.

By the time I was 12, my long-sightedness had corrected itself, and I was able to consign my specs to the dust heap. Four eyes was a thing of the past. Anyway, the taunt never really bothered me. I always knew I could take off my glasses whenever I wanted to. The fat, however, was a different affair.

Puppy fat, my mother called it. It'll soon go. I was determined to help it on its way. At 14 I experimented with eye-liner, blue eye shadow, and dieting. The latter consisted of eating as little as possible until about four o'clock when I couldn't stand the hunger any more.As I matured, I was able not to eat too much from Monday until Thursday, then I broke.

I still believe that had I not joined Weight Watchers, my dieting experiments would have been abandoned along with my roll-on pantie girdle and wet-look mini skirt.That was not to be. Weight Watchers started a group in the Loyola Hall in South Tottenham, and Aunty Sylvie offered to take me. I have to point out that Aunty Sylvie is not the villain of the piece. She, and my mother, wanted me to be happy. If it was slimness I coveted, then they genuinely believed that by helping me to be slim, they would be making me happy The orthodoxy of the time was that dieting was good for women.

And so I went to the Loyola Hall and sat rapt with attention as a petite forty-something in a smart suit preached to us about the joys of slimness and how easy it was to attain. She warned us against the demon double chocolate gateau with old adages such as, a moment on your lips, forever on your hips. Fattening food was sinful. Our bible was the Weight Watchers diet, which was so complex as to require a whole booklet and a good hour's study before it could be understood. New members had to stay behind to go over it.

From the moment our lecturer opened her mouth, I was hooked. Here was a new religion, with rules and rewards - our lecturer was the way, the truth and the life. Salvation was attainable with only two slices of bread a day and weighing your fruit - you must always weigh your fruit. Here, in the Loyola Hall, was another place to shine. I was a high achiever at school, and loved winning glittering prizes. At Weight Watchers too, I knew I could be a star.

I became passionate about my diet. Early Christian martyrs had nothing on me - I majored in mortification of the flesh. I forced myself to eat one liver meal a week, which I hated. I gagged as I ate it. I drank only Marvel skimmed milk and learned to love rhubarb - bowls and bowls of boiled rhubarb with artificial sweetener. And my weight began to plummet.

Dieting was an exquisite agony. I remember very clearly being invited to the bar mitzvah of an affluent school friend's brother at the Savoy Hotel. I stuck to my diet (!!!!). Eventually I hit a 'plateau'. This was Weight Watchers terminology for when your body is resisting the loss of any more weight. I found the plateau discouraging, but I soldiered on The dieting was my proving ground. It was intimate, personal, and by withholding pleasure from myself, I was sure I was doing something good.

This is not going to be one of those stories when the young person in question descends into anorexia or bulimia. I don't know what it was that saved me from an eating disorder, as the causes of eating disorders can be so various, but in the end I couldn't stand the deprivation any more. I began to eat again. I never reached my goal weight at Weight Watchers (which was set impossibly and unhealthily low) and, feeling a failure, I gave up.

And I put the weight back on. Only slowly - I wasn't a binge eater. By the time I went to Oxford I was nicely rounded again. It made me feel that I ought to do something about it. Only it was tough; I was living away from home for the first time, and eating was comforting. I tried to push myself into dieting again by overeating - only an ex-dieter will understand the logic here. If you overeat like mad, than you've got to go on a diet. Stands to reason, mate. So I'd buy a stash of chocolate and open my Mars bar and copy of Our Mutual Friend simultaneously.

I think it was around this time that the dieting/overeating syndrome began to be a sort of displacement activity for me. If things were bad, they would come right again if I dieted. If things were bad, I could eat, and they would seem better. Either way I won, and both ways I lost. My fat became a visible symbol of all the things I didn't like about myself. Dieting - or, more often, thinking about dieting - gave me the illusion that I could change myself fundamentally My low self-esteem located itself in my fat; because I was fat, I had low self-esteem.

But no shortage of boyfriends. I thought it paradoxical that boys I knew never focused on my size - except one, and I dropped him. My self-esteem wasn't that low. I can honestly say that no one important in my life has ever made me feel bad about my weight. I perpetrated my own ego-bashing.

In my early twenties, I hit the slimming club circuit again. Thinking Weight Watchers wouldn't have me back (as if!), I joined the now defunct Silhouette. We stood up at meetings and (this is true) recited together:

I must, I must, I must improve my bust!

I will, I will, I'll make it better still!

Hoorah! Hoorah! I need another bra!

I was 23, I was reading for a BPhil in Mediaeval Studies at the University of York, and I was reciting this, and believing it...

At 25 1 married Brian, who was and still is utterly bemused at my preoccupation with my weight. I remember wishing I was slimmer on my wedding day, and thinking that one fine day, who knows?

Then I started teaching. As any new recruit to the classroom will tell you, being a probationary teacher is one of the most gruelling, exhausting activities ever devised for womankind. I began to eat again. Not only that, being married meant I was cooking more - and eating the results. I put on more weight than ever, and became wildly distressed. I had nightmares about getting fatter and fatter. I was actually scared of what I was becoming.

I went to the doctor. The doctor recommended yet another slimming group, this one run by a psychologist at a local hospital. He gave us a diet sheet and a regime of behavioural science. I lost weight. Once again, I liked losing more weight than anyone in the group. I discovered how easy it was to eat hardly anything at all, The kids at school complimented me on my weight loss. I wore tight jeans and was a size 12.

At last I'd got there. I was slim. But something was bothering me. I went back to the psychologist, a taciturn man with a ginger beard. I told him I was slim now, but I wasn't happy I'd always imagined that when I was slim, I would enter a brave new world.The sun would shine perpetually, and every day would be the first day of spring. I asked him why I was now unhappier than ever, terrified of losing my new-found slimness, still not satisfied with the way I looked, hoping to lose just a pound or two more, to be on the safe side. Why? He said nothing, but looked baffled.

Slowly I put the weight back on again, and then I became pregnant with my first daughter. Bliss. I could put on weight and it was socially acceptable. I revelled in my pregnancy I decided to try the Earth Mother hat on for size. I gave up work, stayed at home, breast-fed and changed nappies.

For me, a big mistake. I became quite depressed, and when we ran out of money soon after the birth of our second daughter, and I had to go back to work, I was overjoyed. And then I took stock.You've guessed it - I thought I needed to go on a diet. I messed around with the F-Plan (who didn't?) and tried just cutting back. Then the mother of a pupil suggested I go to Weight Watchers with her. I was 36. Why not, I said.

Only this time, twenty years on, it was different. I noticed things I hadn't noticed the first time round. How come all the new members were actually re-joiners? Hadn't the diet worked the first time? Why were there pictures of food everywhere in the meeting room? Why were we talking about food all the time when surely it would be more sensible to forget about food? Why were Weight Watchers and Heinz the same firm? Why was the lecturer confessing to her binges in front of us? What was an intelligent woman like me doing listening to this claptrap? Why, if I despised it all, was I still dieting?

I lost some weight, then it was Christmas, and I gave up. I thought, there has to be something better to do with my life than dieting. I decided it would be fun to try writing. I've always had the highest regard for writers, and have swooned at the feet of Doris Lessing, Salman Rushdie et al. It was precisely this high regard that stopped me writing. What was the likes of me doing, thinking she could be like the likes of them? Me -a fat person - what a cheek! But giving up dieting was a liberating time. It opened up new possibilities. It meant I could stop living conditionally (when I lose weight) and actually start living.

I began to keep a commonplace book filled with jottings, and showed it to a writer friend. He read it through and commented favourably on a description I'd written of a big woman I'd observed on the beach. I realised that weight was still an issue with me, and that I had accidentally become an expert in how not to deal with it. Thus the idea for my first novel, A Matter of Fat, was born.

I wanted it to be a comic novel because instinctively I felt that part of the answer to an obsession with weight was not to take oneself too seriously It was a relief for me to expose, through fiction, the crazy dieting behaviour to which I'd become addicted. I wrote of how I'd binge on coming home from a slimming club meeting, confident the binge wouldn't show up on the scales next week, or how I'd weigh myself three or four times a day. I wrote of my own difficulties in adjusting to being a woman who wasn't going to diet again, making one character say that she would be perfectly happy to be a fat woman, if only she could be a few pounds slimmer. I think that sums it all up.

The best thing about A Matter of Fat's success was that so many women identified with the behaviour I'd described in it. That was a revelation to me; I genuinely thought I was alone with my neurosis. Of course I'd read Fat is a Feminist Issue, but that only served to convince me I was fat because I was neurotic. I'm afraid that sanity seemed even further away than slimness. No one, but no one, has perfect parents, and I didn't want to blame my loving mother and father for my obsession with size. That's victim think. In my case, being neurotic had not made me fat; dieting had made me both neurotic and fat.

I always imagined that if my first novel was a success, I would magically grow up and care no more about being big. For a while, in the euphoria of having the novel published, this was true. What authority would I have as the creator of a comic novel slamming the diet industry, if I was slim? It was almost as good as being pregnant. I had an excuse to look the way I did.

Then reality kicked in. I learned that one couldn't overthrow a lifetime of dieting behaviour just like that. The most interesting part of my journey towards size acceptance began after I started to write about the issue.

Firstly, don't you believe anyone who tells you that they were able to make a sudden transformation from being weight obsessed to being anxiety free. Learning self-acceptance is a gradual process. Finding success as a novelist wasn't as helpful as one might imagine. I always felt that the pseudo-glam me at launches and author events was an actress; the real, still rather fat me, was the true Sherry.

The most important thing for me in learning to be large, has been the support of other large women.This is invaluable, even essential. In the beginning, I didn't think I looked very good, but it was easy for me to see that the other large women I knew did look good. Admiring other fat women made me see myself differently. I have to confess that I like to look good. I spend an embarrassingly large amount of money on cosmetics and relish applying make-up. I can't think for a moment that appearance doesn't matter. On giving up dieting, I had to learn a whole new way of presenting myself. That's been one of the most enjoyable parts of the process of size acceptance.

The next thing that's been instrumental in helping me be a happy size 20 has been the explosion of plus size clothes stores. Shopping has become a blissful experience. I can try on all sorts of clothes and only buy the ones that suit me, rather than the ones that fit.The temptation to diet to get into nice clothes is a thing of the past.

These days I observe myself carefully I've noticed that when I'm stressed or depressed, I want to comfort eat and I simultaneously feel fat. When things are going well, I feel good about myself, and become less conscious of the place of food in my life. I can see more clearly how fat, for me, is a solid metaphor for my psychological state. Understanding this helps me to distance myself from a preoccupation with weight. I can unravel my own mind games. Knowledge is power.

What hasn't helped me come to terms with myself? Most prominently, society's new obsession with so-called 'healthy eating'. This is a tabloid age of crude moral certainties, and one of these is that Health is a Good Thing. We hear it argued that it can't be okay to be fat because it's unhealthy. What you look like is now conceded grudgingly to be a matter of choice, but health isn't. The NHS has only so many resources, and fat people tend to get ill. So do those who engage in dangerous sports, smokers, people who go to work in crowded trains and catch flu, people who work too hard, get stressed and weaken their immune systems - but none of these get the constant ridicule and insidious rejections that fat people suffer. I've noticed that among my friends those that seem to take the most time off work through ill health are the fittest - they're always straining their backs at the gym and puffing ligaments whilst jogging. Plump, sedentary people like me seem to enjoy enviable health. Fattism is highly illogical and utterly unjust.

And then there's so-called healthy eating. Everyone is expected to do this.Yet healthy eating is only another word for dieting. Just as downsizing replaced redundancy, healthy eating has replaced the dieting word. So everywhere we go we are met by diets masquerading as eating plans, and women are still being encouraged to relinquish control of their own bodies to some nameless authority who apparently knows better. Few experts are prepared to concede that real healthy eating should be natural, joyful, include reasonable amounts of chocolate and celebratory meals, be neurosis-free and that any form of consistent under-eating will take its eventual toll. As it did with me.

It's a cliché now that images of women affect the way we see ourselves, but like all clichés, it's true. I get dispirited after watching countless slim women on television.The effect it still has on me is to make me feel that in some subtle way, I don't fit. My body, a living history of yo-yo dieting and a couple of pregnancies, is the sort of body, I discover, that one really ought to keep under wraps. So I still feel uneasy about my appearance unless I wear trousers, long skirts, and tops with sleeves. Or perhaps this is just modesty - I hope so!

There's no doubt that I worry much less about weight these days. Back in my twenties, I was either on a diet (starving) or off a diet (bingeing). I couldn't imagine life in the middle. Now, these pendulum swings are far less extreme. I go through phases of trying to cut down what I eat, and then I go through phases of not giving a toss.

The most compelling reason I have not to diet now is my two teenage daughters. The elder is the same age I was when I started my career as a Weight Watcher. Both of my daughters have the same body shape I did at their age.They are rounded, and both very pretty. The younger one enjoys sport, thanks to the new breed of games teacher who encourages rather than humiliates. Thanks, Miss Hill, Mrs Riley and Mrs Ferrol!

Both my girls enjoy food. Every so often I screw up and get them to join in my occasional binges, and I regret it afterwards. When I cut back, they copy me. I've learned a mother has an awesome influence on her daughters. This knowledge guides my behaviour around food, and stops me bad-mouthing myself if I don't like the way I look.

My daughters seem reasonably comfortable with themselves at present, and have swallowed whole my anti-dieting and anti-fattism philosophy, often sounding off about it over the school canteen dinner table. They like occupying the moral high ground! I feel fairly certain now that they won't be fodder for the dieting industry, and they won't torture themselves with feelings of not fitting in, of looking wrong, of there being too much of them.

I'm 45 now, and the good news is that the older you get, the less you worry about size. This is partly because you lose the self-centredness of youth, and get to see that other people are just as important as you, and often more so. The self-absorption of dieting behaviour seems unattractive. A good relationship with another person or with yourself is far more valuable than a good figure. On the other hand, the pain I inflicted on myself through my weight obsession has given me an insight into how to deal with different sorts of self-inflicted pain. Also I feel I have some empathy with others who feel excluded from mainstream society, as I did. These are precious gifts.

I also know there's a point where you realise you are who you are - and you can change your underclothes, but not your true self.

Both my maternal and paternal grandmothers were large women. They were also loving, hard-working, respected women. My mother is large. She's also gorgeous. I want to be like them, just as my daughters seem to want to be like me.