Eating Myself by Candida Crewe (256pp, Bloomsbury, £12.99)
A Shape of My Own by Grace Bowman (304pp, Penguin, £14.99)

Here are two books by women in which the authors write about their relationship with food and their desire to be thin. One of these writers, Grace Bowman, is a former anorexic; the other, Candida Crewe, a former bulimic. I buzzed through these stories with a mounting sense of horror, because they both contain an essential truth, something that is very scary indeed. The scary thing is that Bowman and Crewe, as they both explain, do not live on a strange planet far away from the rest of womankind. Crewe says she thinks about food or weight "every few seconds", and calls herself "normal-abnormal".

Crewe, who binged and starved for years, and who once ate so much food "that I felt I had been kicked and kicked and kicked and kicked in the middle", tells us that she has obsessively studied other women, and that her dysfunction "doesn't wildly differ from that of every woman I have known or have ever met". Bowman, who starved herself down to less than six stone, and who says that the very act of eating felt like sitting in a bath full of spiders, says of other women: "They don't admit it, but they are constantly fighting their own battles against the biscuits. It's what we are told to do ... I am just doing it to a further degree."

Sometimes talking about herself in the third person, Bowman describes her descent into anorexia with clinical skill; if you haven't understood it before, you will now. One of the most beguiling things about it, in fact, is that it feels like an ascent - the head clears, and the starved body, on the lookout for food, becomes vigorous and alert. This is the high, and it helps to explain how anorexia, like gambling or cocaine, can become an addiction. '"I felt better when I ate less," she tells us. "My addiction to not-eating was actually an addiction to feeling better, to feeling fixed."

Just as important, though, is the fact that anorexia, for adolescent girls, "is often a physical manifestation of the rejection and fear of growing up". Bowman was a diligent schoolgirl from a close family in a northern town. She tells us that she always got top marks at school, and you realise that she came to rely on being perfect, on the ticks, the stars, the smiles of teachers and parents. And then along came something like the monster in a horror film - adulthood, with its accompanying confusions and mixed messages. Bowman had been in a world she could control, and here was this new, out-ofcontrol world looming.

Her answer: "Got to be thin! If only I were thin. That's it."

Bowman says that, as a "good girl", the girl who always came top of the class, she was scared of growing up; she did not want to rebel. The disturbing thing here is that we still live in a society in which growing up, for a woman, can be associated with rebellion and transgression. Disturbing, but true. A lot of anorexics, says Bowman, are girls who grow up wanting "to please their parents and to be universally liked". And then they starve themselves; you realise uncomfortably that something out there is telling these girls that being a woman might harm their chances of being liked. "Anorexia," writes Bowman, "is my security blanket."

I was going to say that Crewe's book is less disturbing, because she maintains a superficial cheerfulness throughout, but maybe this is not quite true.

Like Bowman, she has a deep well of anger, and you can sometimes see this anger glinting through her charming prose like a dagger. "If I think about it long enough," she tells us, "fashion makes me crazy with anger, what it has done to women." Fashion has a lot to answer for, she says, "in terms of making women feel shit about themselves". Fashion is a "bully", and it has a "gang", and it makes women feel excluded. So it's interesting, and rather chilling, when Crewe tells us about a shopping trip with "a friend who is a fashion editor at Vogue". They go to Valentino, to Gucci and to Prada, and you suddenly realise that Crewe has made a brilliant point - she hates fashion, but she also somehow completely accepts it; fashion has, in some ways, won. Like Bowman, Crewe has spent most of her life slim or even thin, and one of the great things about this book is the way she explains, using lots of anecdotes, how it is possible to be slim, and yet to feel fat. She tells us that she hugs the walls at parties, to minimise the presence of her bottom, and that she wears her hair long, for the purpose of camouflage. But why does she want to be thinner? She explores all the possibilities. Not to attract men (she's happily married), not to compete with other women, or to impress her mother, nor even for herself.

So why? Perhaps there is a clue towards the end of this book, when Crewe tells us how she felt about writing it. "I did not want to upset anyone," she says. When she writes about her eating disorder, she wants to put it firmly in the past. "It is important for me not to dwell too long on my past extremes," she tells us. "I want to forget about all that nonsense, throw caution to the wind, and get on with other things," she tells us. Such as "lurching, inching" towards normality.

These are brave, revealing, and shocking books, sometimes as articulate in what their authors leave out as in what they keep in. Women, I am certain, will identify with both stories. But I also recommend both books to men. Guys, if you've never thought much about this stuff, it's time you started.

· William Leith's The Hungry Years: Confessions of a Food Addict is published by Bloomsbury.