For Gordon Ramsay it's a fry-up, for Heston Blumenthal a curry and for Angela Hartnett a custard tart. Here our restaurant critic Terry Durack (crisp bacon, roast duck, dill pickles...) meets the scientists trying to discover the secrets of our powerful food cravings - and how to control them. Piece of chocolate anyone?

For Tom Aiken, it's toast with lots of butter and thick-cut marmalade, and baked rice pudding (with skin) and raspberry jam. For Gordon Ramsay, it's cafe latte, shepherd's pie and a good fry-up.

The Ledbury's 26-year wunderkid, Brett Graham, goes for spicy salt-and-pepper squid and his mum's salmon lasagne, while The Connaught's Angela Hartnett is a sucker for Swedish crisp rolls, Bovril and custard tarts. Anthony Flinn, of Leeds' ground-breaking Anthony's restaurant needs chocolate milkshakes in order to survive, while Paul Hitching of Manchester's Michelin-starred Juniper is addicted to olives, bees' pollen and cherries - probably all at once, judging by his no-holds-barred menu.

We all have special foods we crave - things that satisfy some primitive, primeval need deep inside us. They could be a reminder of distant childhood pleasures or simply something in stark contrast to the normal, sanctioned food that we eat every day. Cravings are the foods reach the parts that other foods can't.

Even Heston Blumenthal will forsake his whiz-bang gadgetry and mad-scientist laboratory when satisfying his innermost desires - namely for Indian takeaway. "I go to France every year on holidays and eat all this wonderful food but they just don't do Indian in France," bemoans the creator of snail porridge with jabugo ham and white chocolate with caviar. "So, by the time I get home, I'm gasping for it."

Some food is too sensible to crave. Nobody craves porridge, they just eat it. If my doctor said I could never eat alfalfa sprouts again, I'd dance out the door singing. Ditto rice cakes, wheatgerm, or cabbage. So who decides what is craving material and what isn't?

Apparently it has a lot to do with sex - not so much whether you're getting any or not, but what gender you happen to be. According to the University of Washington's Centre for Public Health Nutrition in Seattle, boys crave different foods to girls.

Men are apparently drawn to anything loaded with protein, salt and fat, as in roast beef, burgers, fries, steaks, pizzas and chips. Think Homer Simpson with a blissful look on his face. "Mmmm. Hog fat."

Women, on the other hand, are more your high-sugar, high-carb cravers, with a wish list that runs to sweet biscuits, ice cream, pasta, bread and, need-it-be-said, chocolate, in any shape or form. In America, as in Britain, chocolate is by far the most craved food item, followed by pizza a fair way back in second place. This suggests that there's a vast market for a 24-hour chocolate home-delivery service.

Cravings are cultural as well as emotional. They spring from familiarity. So Jaffa cakes don't rate highly in China and there is very little lusting after fermented beancurd or dried shrimp paste in the West. Economics can also drive cravings. If you were once allowed a spoonful of caviar but were never able to afford it again, then bingo, you are doomed to crave the unattainable forever more.

I like to mix up my cravings, so that some are Topshop, some designer, some vintage and some of my own sweet invention. A few are constant, old friends - garlicky dill pickles, salty anchovies, fat pork sausages, crisp-but-not- too-crisp bacon, good old spag bol, lacquered Cantonese roast duck, and Vegemite - while others are strongly seasonal, such as ripe tomatoes in summer, and crisp Pink Ladies in winter. Still others are so strongly associated with a time, place or person that it all gets very confusing as to whether it is the food I actually crave, or the time, the place or the person.

For years, I believed these cravings were simply my body reacting to some nutritional need. If I had exercised too energetically, then the depletion of my glycogen stores would lead me to crave carbohydrates to counter the loss, hence the need for a sausage sandwich. When hungover and requiring vitamin B, the Vegemite craving would kick in. If down on Vitamins A and C, my brain would make my hand reach out for tomatoes. Heaven knows what nutritional depletion brings on a craving for garlicky dill pickles. Sometimes, it's best not to know.

Alas, this attempt to justify my own weaknesses has been exposed by Professor Marcia Pelchat of Philadelphia's Monell Chemical Senses Centre. Pelchat placed a test group on a liquid diet that provided all the calories, vitamins and minerals they needed, yet they still craved certain foods. She determined that cravings are more a psychological need than a physical one; not things the body required, but simply things it desired.

According to the University of Washington's Adam Drewnowski, this psychological need is often triggered by stress. To compensate, our bodies drive us towards food rich in fat and sugar, which can boost the brain's supply of feel-good endorphins.

But what about pregnant women and their well-documented cravings for the weird and wonderful? Madonna apparently ate eggs and olives when she was expecting; Jordan hit the curry; Victoria Beckham went strawberry mad; and Julia Roberts was reported as fancying French fries dipped in chocolate. While pregnancy cravings are generally thought to be caused by the sort of massive hormonal changes experienced during pregnancy, some believe that by satisfying her cravings, the mother is instinctively providing the extra nourishment that her baby needs. The experts are sceptical of both theories, and so am I. Who is to say that these girls didn't chocolate-coated chips all their lives? I wish I could get pregnant, I'd have a field day.

The question is, should we give in to our base desires or try to control ourselves? After all, most of the foods we crave are either bad for us or fattening, or both. Most so-called experts suggest some form of control.

One suggests eating a banana whenever you feel overcome with an urge for chocolate. Another recommends dealing with a "bad" craving by giving in to something not quite so bad, such as having gelato instead of ice cream, nuts instead of potato crisps, and roast chicken instead of fried chicken. This is only a problem if, like me, you crave gelato, nuts and roast chicken in the normal course of events anyway.

The silliest advice I have come across is to keep all the lights shining brightly, on the basis that dim lighting tends to lower inhibitions. I tried it and can report that bright lighting makes it much easier to find the Pierre Marcolini chocolates hidden at the back of the cupboard.

The best theory comes from Richard Mattes, a professor of foods at Purdue University in Indiana, who says that unless you are trying to lose weight or are on a medically restricted diet, then it is far better to give in to your craving, thereby keeping it from getting out of hand. He even goes so far as to say that you could do more psychological harm than good by denying a craving than by indulging it.

So Tom, eat your rice-pudding skin; Gordon, scoff that fry-up; and Heston, get extra vindaloo and poppadums with your next Indian take-away. Me, I'm off to buy another jar of dill pickles. After all, why do any more pyschological damage to ourselves than strictly necessary?