The Daily Telegraph

Like most people, Julia Fitzgerald began to pay attention to what she ate and drank only after she became ill. Ten years ago, aged 22, she suffered whiplash following a car crash.

A year later, when she was still in pain and taking medication that made it hard for her to concentrate on her work as a geophysicist, devising computer programs, she was finally diagnosed with fibromyalgia (chronic muscle pain) but the only treatment she was offered was antidepressants.

"That's when I started to take an interest in my diet," she says. "Until then I hadn't been eating badly - but I wasn't getting my five fruit and veg a day. I was drinking large amounts of coffee, but not much water. And I didn't have much oily fish, which has an anti-inflammatory effect. After I became more careful about what I ate and drank, I soon found that I didn't need the painkillers."

The huge improvement in her wellbeing inspired her to retrain in nutritional therapy at the University of Westminster, a three-year degree course including 300 hours of clinical practice. Since completing it, she has been in private practice in Devon advising others on how to maximise their health. "You may not be sick now but that doesn't mean your diet isn't harming you," she says. "It could be increasing your chances of getting a range of degenerative conditions, including diabetes, dementia and cardiovascular disease. For example, boosting your calcium intake will reduce your long?term risk of osteoporosis."

In private practice she tailors diets to individuals: clients may want to lose weight, deal with irritable bowel syndrome, give themselves an edge in a sport or tackle depression - all areas in which she believes good nutrition can have an impact. She also takes group sessions at FitFarms, a residential programme that kickstarts people into a healthier way of life. "Many of those I see drink regularly because it has become part of their lives. They don't realise how much damage they are doing to their livers."

Recognising bad habits is the first step to change, so she asks clients to keep a three-day food diary. Then she discusses changes such as adding protein to their breakfast or increasing variety. Moderation is her watchword so, although she is concerned about the prevalence of processed foods, chemicals and refined carbohydrates in the modern diet, she doesn't ban anything.

"If you do that, you feel deprived and cheat," she explains. "A lot of people eat too much wheat and feel better if they reduce it, but I don't tell them to cut it out. I used to eat a lot of pasta myself; now I have it occasionally. Many people are also intolerant of the lactose in milk and find a large latte indigestible, but are fine with a yogurt or cheese. Eating wheat and dairy is still relatively new for our bodies, as agriculture only has a 12,000-year history and we are still getting used to those foods."

She advocates three meals a day, interspersed with healthy snacks such as nuts, dried fruit or hummus and sticks of raw vegetables. She also advises restricting carbohydrates to the early part of the day and adding in more fruit, veg and oily fish rather than taking other foods out.

"And rather than telling people to cut out alcohol, I suggest they try elderflower or lime and soda a couple of evenings a week. Nor is there any need to drink two litres of water a day, as is frequently recommended, as long as your urine is pale."

Fitzgerald advocates the 80/20 rule: eat as well as you can for most of the time and don't chastise yourself when you lapse - which you inevitably will. This avoids the unhealthy blow-out.

One of her main concerns is that some nutritionists go to extremes, putting women who suffer from bloating on long-term anti-candida diets, for example. "There is evidence that a low-carbohydrate diet for a couple of months, in combination with anti-fungal pills [candida is a fungal infection], does inhibit the bug. But some people stay on that diet permanently, which isn't good, and candida is also often blamed for a whole range of infections and conditions that cause similar symptoms."

And the recent flurry of debate over whether taking antioxidants such as vitamins A or E can actually shorten lives by interfering with the body's natural defences may also be overstated, she believes. "The trials cited involved large amounts of single nutrients. Nutritionists use smaller doses in combination, in keeping with how nutrients occur naturally."

But most of all, she urges people to understand the nutritional approach to health is not a quick fix. It takes time, money and effort: "It's not about miracle cures but about reducing risk and, in the process, suffering fewer niggling pains, skin problems, and hormonal swings while having more energy and a clearer brain," she warns. "My fibromyalgia isn't cured, but it isn't nearly such a burden to me these days."

Five ways to improve your nutrition

1 Concentrate on what you need to add (fibre, five fruit and vegetables a day, good fats) rather than what you need to take away.

2 Stick to the 80/20 rule: eat healthily 80 per cent of the time and don't worry when you lapse.

3 Eat more slowly and chew food properly to assist digestion.

4 Note symptoms such as constipation, diarrhoea or bloating: make changes to your diet before, not after, you become ill.

5 Stop thinking of food as fuel: take an interest in where it comes from, new ingredients and new styles of cooking.