Joanna Briscoe: Ladies, don't waste your life on lettuce

Skinny women are back on the agenda, which is where they tend to be most comfortable. As the barking old size-zero row rumbles on, the latest news from Slenderville is that the actress Keira Knightley is suing the Daily Mail for running a photo of her looking somewhat slim alongside an article on the dangers of anorexia. She, of course, has always made it clear that she doesn't have an eating disorder. There's no doubt in my mind that fat-free celebrities have an effect on poor vulnerable girlies and their eating habits, but pointing the finger at individuals and guessing at their eating habits is a dangerous game.

What clearly does suffer from an eating disorder, however, is our country's mindset. Yeah. Like, our culture.

A recent survey claims that women spend an average of 31 years of their lives on a weight-loss diet. Well that's funny, because men seem to spend an average of 74 years of their lives on a beer, eat-what-you-like, and-never-think-about-it diet. Which regime is more effective, we ask. They come out about equal in my opinion. Men may end up hoiking pendulous guts and women swinging bingo flaps, but neither sex out-lards the other. So what were the 31 years of suffering for?

One would also like to point out suitably early on that women in some areas of the world spend 31 years on a diet too - a near-starvation and malnutrition diet - and then die because that's the sum of their life expectancy. Think about that. It's an outrage. If we're lucky enough to be able to afford sufficient food, we should buy it well, and then eat it.

Readers, diets don't work. They do not work. We've been told this. We know this. It's true. Diets don't work. Dieting makes you fat. An estimated 90 per cent of dieters regain the weight lost, and then pile on a few more wobble layers because they've mucked their metabolisms about to the point of bemused inertia.

Unfortunately there's girly bonding at play in the I-am-female-therefore-I-hate-loads-about-the-way-I-look approach as women gather in the office kitchen with their crispbread, tuna salad and low-fat yoghurts in a variety of flavours: saccharine and aspartame. More than a fifth of British women consider themselves permanent dieters, poor loves. It's tragic. They should have got over it by Year 11. Climb off the treadmill, chuck out the sweeteners, read The Beauty Myth and your mum's copy of Fat is a Feminist Issue, get a life, and, above all, bugger the diet.

Right, the feminist lecture is over. It's all true - but sadly it's not quite as simple as that, is it?

Even we brainy females, consciousnesses loftily raised, politics, experience and gut instinct all gliding along in glorious harmony, would secretly like to lose a few pounds, still experience the ghost of "fat" days, and feel subconscious little twinges of self-loathing based on the current state of our lard-o-meters and on how many fashionably emaciated images we've subliminally absorbed from the net and newsstand that day. Along with the average woman, I blurrily fancy losing about half a stone if I don't have to do anything for it. Along with the writhing contradictions that can inform our relationship choices, this is our area of deepest irrationality.

I starved myself at 17 to a state of light-headed coltish slenderness, or so I thought. Retrospectively, I was just pinched and pale. I'd wolf a packet of Revels but literally weigh cucumber for its calorific value because my diet was starting after mid-day. And so on. Mind and metabolism formed a delighted dysfunctional partnership.

I realised at 20, thanks to a good relationship featuring healthy home-cooked meals, that dieting was wrecking my life and I'd never do it again. My position now is that there lies a middle way that we're programmed not to think about or to inhabit. It involves being neither fat, nor as slim as fashion dictates, but being able - with a few culturally induced slip-ups - to mute that internal hum of body hatred, and accept that middle ground.

And yet, as I write this column, it is sinking in that this means I'm never going to be the shape of the latest 18-year-old Wag. A quiet buzzing in my brain is still telling me that although I'm a size 12 with curves and would look demented in half Topshop's stock, this is what I ought to aspire to.

The feeling that we just should be skinnier is where we retreat when we're feeling low in confidence, an excuse for postponing life. Is there ever a way past it? And if we civilians still feel the pressure, what's it like for young actresses such as Keira Knightley who work in an industry of starveling-sized Mass Body Indexes?

Oh, and size 12 is now on the large side, apparently. Well my curvy arse to that. Medium is the new zero. If we think it enough times, we might just begin to believe it.

'Sleep With Me' is a novel by Joanna Briscoe (Bloomsbury)

Rowan Pelling is away