Doctor's city survival diet

It is one of the ironies of modern life that as we urban types become more concerned about our health, the environment in which we live and the daily punishment we inflict on our bodies becomes steadily worse.

We drink too much alcohol, tea and coffee. We're assailed by pollution, pesticides, toxins and nutrition-free junk food. We work in air-conditioned offices, enslaved to VDUs. What we need, according to Ian Marber, a leading nutritionist also known as The Food Doctor, is a diet tailored to cope with the onslaught, the "total toxic load" of city living.

Hence his latest book, The Food Doctor in the City. There are, for example, he warns, thought to be about 500 chemicals in our bodies today that simply wouldn't have been there 40 years ago. "I don't preach," says Marber. "But people should think carefully about what they're eating and what effect it has on their bodies and on their ability to perform during the day."

If the idea of eating health food leaves you cold, it may comfort you to know that two top restaurants, Prism, in Leadenhall Street, and The Fifth Floor Cafe at Harvey Nichols, are putting Marber's recipes on their menus. And if they're good enough for them ...

Marber doesn't hold with all the shibboleths of the health food industry, least of all the organic bandwagon. "People think that if something says organic, it's automatically good for them, but that label often lulls them into a false sense of security. Organic food is only good if the original was healthy in the first place - naturally low in sugar and salt," he says.

Nor is juicing - last year's grooviest health-food fad - necessarily a good thing. "Again," argues Marber, "people think if they have a juice they're OK. A glass of juice does deliver vitamins in a form that is easy to digest, but juice lacks the fibre you find in whole fruit and vegetables and it introduces a large amount of sugar into your bloodstream very quickly, which can lead to a feeling of drowsiness later." Keep up your fruit and vegetable intake, he suggests, and eat a whole piece of fruit with your juice.

When it comes to nutritional advice, most people are desperately looking for an approach which means that somehow they can go on eating bags of Danish pastries but still qualify as a Healthy Being. Alas, that's not on the cards. There is no magic bullet for health. One of the book's main messages is the need to control your blood-sugar levels. It might not sound riveting but, says Marber, it is vital for urban survival. "Blood-sugar levels fluctuate throughout the day according to what we eat and drink," he explains. "People often suffer from energy highs and lows, and during the lows - typically around four o'clock - they suffer fatigue and cannot concentrate."

The answer is not to nip out for tea or coffee, since this will simply add to the blood-sugar fluctuation, but to combine protein, fibre and carbohydrates at every meal and replace stimulants with water, juice, seeds and fruit teas. It's not very tempting, though, is it? "You'll soon get used to it and you'll find the benefits worthwhile," he says.

Marber doesn't pull his punches. Chocolate and cola are bad news, not just for their stimulating qualities, but because of more farreaching effects. "Just 100 grammes of refined sugar can deplete the immune system by 40 per cent for five hours," he explains.

Alcohol is out, too. "It has to be processed by the liver, whose job is also to filter out toxins. So do without a drink for a few days every week and give your liver time to tackle those other toxins," he advises.