At The Hempel, Lady Weinberg's chi-chi new hotel, restaurant diners are asked if they have any allergies before their dinner orders are taken. The Good Health Clinic, a natural health centre in London, will wire you up to a "Bicom" machine to rid you of food intolerances. And clinics at the Institute of Optimum Nutrition, an educational trust, are now booked up three months in advance. So why are we flocking to the nutritionist?
"People are aware now that low-grade health is related to what they eat," explains Kate Neil, the Institute's director of academic studies. "We don't just have asthma or eczema sufferers but many of the 'vertically ill' - people who simply feel irritable, depressed or lacking in energy." Methods to test food intolerances involve strange names and even stranger pieces of equipment. There's applied kinesiology (a machine measures "energy frequencies"), vega testing (food intolerance is measured by electrical current) and trace- metal hair analysis (a nutritional history is diagnosed from your tresses). Consultations and treatments can cost up to pounds 200.
Nutritionist Vicki Edgson has been practising from her Sloane Street clinic since September and her clients include fashion designers, actors and top business-people. "People come to me with typically 20th-century ailments, like chronic fatigue and digestive problems. The most common food intolerances are wheat and dairy and I recommend clients stop eating these foods for three weeks. Then I reintroduce them to see if their symptoms come back. Also, businessmen want to know what the best 'brain food' is when they have their power lunches."
But does any of this work? Interior designer Kelly Hoppen started going to see Vicki 18 months ago. "My nutritionist is brilliant," she enthuses. "She calls me every Monday and discusses my diet for the week, although it's a bloody nightmare sticking to it. I have to drink rice milk and eat tapioca bread or brown rice bread which is disgusting. Yet, I feel better than I've ever felt."
However, some people have found the whole nutrionist experience an expensive and ineffective process. Olivia Smith, a lawyer, has been going to a nutritionist for nearly a year. "On my first consultation the nutritionist told me my liver was very toxic," Olivia recalls. "Then she prescribed several supplements and gave me a very restrictive diet to follow. I couldn't eat dairy products, wheat, sugar, alcohol, citrus fruits and very small amounts of specific vegetables. I lost weight, which was a big boost, but about a month ago I just had this terrible craving for chocolate and cakes and felt incredibly guilty after I'd indulged. Now, I feel more tired than I did at the beginning. So far it's cost me about pounds 1,600."
"Anyone can be a nutritionist, because there's no State-registered qualification," says Siobhan Hamilton, director of information at the British Allergy Foundation. "People call up our helpline because they have spent pounds 60 on an allergy test and been sent away with no dietary advice at all."
Restaurant critic Emily Green is also sceptical. "Rather than admit they don't like a certain food, people will say they're allergic," she says. "We're clogging up the planet with cars, smoking and drinking ourselves to death and there are airlines who ban peanuts because the dust can get into the cabin atmosphere. You're more likely to be hit by a flying object than die from a food allergy."