Bridget, save me from orthorexia

There's a pyramid of little tubs of food supplements on my kitchen table. I count them out each morning like a myopic Chinese money-lender - one Co-enzyme Q 10 for energy, one Vitamin E for the heart, one antioxidant for protection against free radicals, one multivitamin just in case ...

I wash them down with a mug of freshly sliced ginger in hot water (I haven't drunk coffee in weeks, no more caffeine overload). The tricky bit is remembering to drink a glass of warm water half an hour before I eat in the morning, an Ayurvedic trick to aid digestion.

I twiddle my thumbs and clean my teeth for an extra long time while I decide how to start the day: fresh fruit which is delicious but, truthfully, leaves you starving before 11am? Organic porridge oats with a freshly grated apple? Organic muesli with an extra spoonful of pumpkin seeds for the essential fatty acids and a dollop of live organic yogurt? I haven't had hot buttered toast for ages and I can't remember what a croissant looks like. I am not on a diet. Oh no, I am in danger of becoming orthorexic. Let me explain.

Being an orthorexic is not about counting calories, like Bridget Jones. The only thing BJ and an orthorexic have in common is they know the value of everything. For Bridget and her sisters, it's cigarettes (10), Chardonnay (9 glasses) and kcals (350 plus 2 Pringles). For the orthorexic it's X milligrams of zinc. To update herself, Bridget's daily mantra would have to list the RDAs of every known vitamin from A to B12, as well as chanting the names of all essential minerals and knowing the proterin value of quinoa versus aduki beans. You can't do this stuff in half measures.

According to Dr Steve Bratman, an American specialist in eating disorders, the new syndrome orthorexia identifies people who are so obsessive and uptight about the quality, nutritional value and moral purity of absolutely everything they eat and drink, the effect is just as self-destructive and antisocial as your common or garden bulimic or anorexic. You might not die of orthorexia (though you could get very lonely) but it puts us high-minded, "my body is a temple" haunters of organic food stores on the same self-destructive level as the teenager who throws up after lunch.

"Ortho" comes from the Greek word meaning " correct", as in "orthodoxy" or "correct teaching". And it is true that no other form of eating combines applying the latest nutritional information and research with such a frightening amount of moral zeal. It takes more effort too, certainly more than chomping on a thoughtless diet of Sugar Puffs, cappuccino, takeaway sandwiches and a late supper of crisps and vodka.

Your orthorexic feels sorry for anyone who thinks you can nullify the effects of the vodka by diluting it with Vitamin C, Vitamin A, iron and potassium-packed cranberry juice. No, to be orthorexic involves radical renunciation.

There are an increasing number of books on nutrition cramming the shelves of your local health food store that will make it clear that you have to choose. Choose between the weaselly compromises most of us try in an attempt to be healthier and a radically pure approach that will have you forking out enormous sums of money on food supplements and dawn-fresh radicchio. It is like a religious conversion. One minute you're counteracting an almond croissant with a lunch of salad leaves, a bottle of Cabernet Sauvignon with a bottle of Evian, a runny slice of Brie with the wholemeal, stoneground organic slice of bread beneath. The next minute the word "Detox" leaps out at you from a magazine cover, and before you know it you're chucking the entire contents of your fridge and replacing them with cucumber, alfalfa sprouts and low-sodium mineral water.

What holds most women back from the brink of full-on orthorexia is the fear of becoming obsessive and losing all their friends. When we encounter the potential orthorexic we experience them as a little sad and weird.

I once flew from Los Angeles to London next to the only woman I've ever seen on a plane doing what they tell you to do - eat no airline food and don't drink alcohol. She snuggled up with a pound of apples and two litres of mineral water and ostentatiously slept her way through meal

service, quite taking the fun out of my freebie champagne.

I am still scarred by the girl a friend brought to dinner who was on a fast. It was all very well for her, treating her body like a temple, but the effect of her sitting there purifying herself smugly at my dinner table was to turn everyone else's food to ashes in their mouths. And I'll never forget sharing a room on holiday in India with a woman whose luggage contained a complete survival diet of vitamins, muesli and - I promise - an electric kettle.

Every potential orthorexic reaches a moment of self-revelation when they realise that they're either going to have to compromise or stay at home alone juicing beetroot and celery for ever. If your diet is so weird that you find you're eating it alone, then it doesn't matter how temple-like your body has become, it may be time to re-evaluate. Prepare something delicious that you can offer to your friends - while you've still got some. And make sure you see Bridget Jones, the movie, when it comes out in April. Two sticks of celery taste so much better washed down with a glass of Chardonnay or two.