Tomatoes are good for you, right? They're packed with vitamins and cancer fighting properties. So when I fill out a food questionnaire for a nutritional therapy student at the University of Worcester, I happily put tomatoes as my favourite food.
I've also filled in a three-day food diary. I think my diet is pretty good. No takeaways; plenty of vegetables. Maybe I forget to write down that single chocolate and give a conservative estimate of my weekly wine intake – but then, doesn't everyone lie a bit?
No, says Safia Sawal, a nutritional therapist based in Birmingham. People come to a nutritional therapist as a last resort, she says. "They've been to their doctor and [have been] told: 'You're just stressed, or you've got endometritis, now off you go and deal with it'. By the time someone's saved up £50 to see a nutritional therapist, they're not likely to lie, and they're very motivated to change their diet."
Sawal's interest in nutrition started because of her 15-year-old daughter, who goes into severe anaphylactic shock if she eats dairy produce or shellfish. Fifteen years ago, there was little support for this type of allergy and Sawal had to learn as much about nutrition as she could.
Today nutritional therapy is a growing field, though it's not without controversy. It's based on the idea that good nutrition helps keep the body well. Therapists can't diagnose, or claim to treat, medical conditions. But they can give food and lifestyle advice as well as nutritional supplements.
Worcester is the first university in the UK to have a postgraduate course in nutritional therapy, though there are plenty of general nutrition courses available. The MSc began in September 2006 and it lasts 24 months part-time, including clinical practice.
Nutritional therapist and course leader Dr Denise Mortimore says there was a need for a higher-level course among practitioners. At the moment, however, anyone can call themselves a nutritional therapist, as the title is not protected.
Sixteen students enrolled in the first year and double that last year. Some are nurses, others are sport therapists. One graduate practises in Chelsea where she "treats celebrities and is fully booked", says Mortimore.
Critics of nutritional therapy say it's not real science. Mortimore insists it is. "We're evidence based. Our students do a lot of literature-searching, they know how to cite properly and they know about quite sophisticated supplements that, in the wrong dose, can make you quite ill," she says.
Student Ella Parry believes that in 20 years nutritional therapy will be as popular as homeopathy. Two years ago she hadn't even heard of it, now she wants to set up her own practice.
Today I'm her guinea pig. We're sitting at Worcester's St John's campus nutritional therapy clinic, which is offering free consultations. There's a two-way mirror, behind which Sawal is observing the consultation process.
First we discuss my medical history – do I have mercury fillings? Mercury, says Parry, is released as a vapour and affects the liver. Have I ever been on antibiotics? These, she says, affect the digestive system.
I'm asked to list my heath problems, the major one being a bad knee. I've been told it could be early arthritis. I've had an X-ray, which showed nothing, and several months of physiotherapy.
Then we discuss my food diary. Parry says I need to avoid foods that cause inflammation. To my horror, I'm told to cut out the "nightshade family" for four weeks: no peppers, potatoes, aubergines – or tomatoes.
I should eat more oily fish, but avoid farmed and larger fish because of toxins. And I need to get some flaxseeds, pine nuts, quinoa and fresh ginger. I'm also recommended a vitamin supplement at around £14 for a month's supply.
I'm a bit alarmed when I'm then offered a 10 per cent discount if I get it from a certain distributor, although Parry stresses it's up to me whether to buy it.
Isn't this all a bit expensive and self-indulgent? Sawal, who is now back in the room, says not. "People come to a nutritional therapist because they're really ill, perhaps with depression, and if I get them to reduce their sugar intake, for example, it can make such a difference to a miserable life."
My consultation with Parry takes an hour and a half, whereas at a GP I'd be lucky to get 10 minutes. There's only one thing on my mind, however, as I leave: I'm really, really hungry. I'd give anything for a pizza, a lovely pasta sauce – or just a plain old tomato.