Fitney Spears

she is doing what young women all over the world, famous or just ordinary, do best: taking it out on her own body.

Rather than addressing the deep-seated issues that have ended with several spells in rehab, she is embarking on a rigorous, military, boot camp-style regime of extreme dieting (six mini-meals of raw food a day) and exercise, as well as frequent visits to a clinic in Las Vegas with the incredibly dubious name of LipoDissolve.

This woman is rich, she is young (only 25) and she is beautiful but still, still she feels the need to beat herself up and to be as physically perfect as she can be, shrinking from a UK size 10 to a size 6 in a matter of weeks.

When Britney first came onto the scene she was carrying a certain amount of puppy fat, and it suited her.

But now, the once ample breasts have all but disappeared, and her thighs and arms look all sinewy and scrawny.

Eating disorders and celebdom

We have seen it all before, haven't we, what with Geri Halliwell and Victoria Beckham and Kate Beckinsale, celebrities whose body mass index shrinks alongside the dwindling fame and the lack of recognition.

Young women who suffer from eating disorders tend to be high achievers. They set themselves targets, and they stick to them.

And those young women who achieve fame in a ruthlessly competitive industry like the music business are susceptible, once the chart position starts to drop, to eating disorders and excessive exercising.

Look at Joss Stone, who despite being successful and pretty is always being told by her record company to get a personal trainer, to lose the puppy fat.

Or look at Amy Winehouse, who went from voluptuous to scrawny in seconds flat.

I had lunch last week with a very famous 41-year-old mum who told me she had spent all her adult life on a diet, that she had been terrorised by the prospect of her bum being photographed while on a beach holiday, but that she was fine now, and at peace with her body.

She nibbled a Greek salad, omitting to eat the cheese, and drank only still water. It is pathetic and ridiculous that we allow our lives to be ruled by some arbitrary measure of what size is acceptable.

Constant yoyo dieting (I am sure such an extreme lifestyle will soon mean Britney is back on the pretzels) is both ageing (not just because of the constant worry about how you look, but also because of the effects of deprivation of essential nutrients) and ultimately fruitless.

Your body simply learns how to survive on less and less food. Anyone suffering from mood swings or more serious psychological problems needs a diet-and-exercise regime that takes those problems into consideration.

Too little fat in your diet leads to depression and feelings that you are being persecuted.

Too little protein means you are weak, and prone to mood swings. Too little roughage means you will be tired and lethargic.

Role model?

Like it or not, Britney is a role model for young women, and this endless self-flagellation followed by complete lack of control isn't a good example to be setting.

Much as I dislike the fact Kate Moss is so revered by teenagers, at least she doesn't try too hard, and doesn't seem to be that bothered by her appearance, never having lifted anything much heavier than a fag.

And, let's face it, the area Britney most needs help with is her awful fashion sense.

Pastel, velour tracksuits, minuscule skirts and slutty cut-off Tshirts might just about pass muster on a pretty teenager, but once you pass 25 and become a mum that look is very difficult to pull off.

I once did a cover shoot with Britney, when she was about 19, and although it was very hard to find designer sample clothes that fit her - she is not very tall, and at that age had a small waist, muscular thighs and a big bust - she looked incredible in a combination of Dolce & Gabbana and Versace.

She has never developed her own fashion style, and unlike Scarlett Johansson (also small and curvy), has never had the accolade of being picked for the ad campaign of a big brand.

The only comfortable fit, image wise, at the moment would be Primark.

She needs to hire a really good, cutting-edge stylist who could help her look a little more, well, grown-up.

I really hope that, sometime soon, women find someone other than a demented Barbie doll to look up to.