How healthy are macrobiotic and vegan lifestyles? Sarah Edgehill talks to three people who have abandoned 'normal' diets
Susie Miller, 32, is a fruitarian and works from home

"I'm attracted to fruit, salad vegetables and sprouted seeds such as alfalfa and sunflower. I never need sauces or dressings with them. My tastebuds have become so refined that I get wonderful tastes from simple foods. I lost a stone when I first switched to raw food, but my weight then went up a bit and has now stabilised.

"It takes a while for the body to adapt, but my eating habits didn't change overnight. I have masses of energy and sleep very little. I used to need at least eight hours. Now I'm happy with four.

"It's the easiest diet for socialising or going on holiday. Almost everywhere you go in the world there's fresh local produce, and what restaurant can't provide a green or fruit salad?

"Since I've been eating raw food, I haven't had a cold. My immune system is so high now that my body is working exactly as it should."

Daily diet

Breakfast: Half a medium-sized melon

Mid-morning snack: 2 apples, 2 pears

Lunch: Salad: half a head of chopped lettuce, 6 tomatoes, grated carrot, half a red pepper, grated beetroot, sunflower sprouts, herbs

Mid-afternoon: Handful of tomatoes, apple

Dinner: Melon, grapes, apples, oranges

Nutritionist's comments

Fruit and vegetables contain a variety of nutrients, but not in the quantities Susie needs. Protein is vital for the growth of body tissues. We ideally need up to 1g per kilogram of body weight, per day. So Susie needs up to 50g of protein. An average eating apple contains 0.4g of protein, and a portion of melon contains 1.1g. She would have to eat up to 70 portions of fruit a day to achieve her recommended protein intake. The biggest single nutrient likely to be missing from this diet is B12, which comes from animal sources. It is needed for the maintenance of the nervous system. In the short term, a lack of this can lead to pernicious anaemia. In the long term, it can result in neurological damage.

Her diet is extreme. The bottom line is that when you restrict the variety of foods eaten, you lay yourself open to future nutritional deficiency.

Anna McKenzie, 48, is a macrobiotic and a professional caterer

"When I was 28 my then boyfriend developed an ulcer. He went to the doctor and took pills - nothing worked. Then he met a macrobiotic counsellor who advised him to cut out coffee, milk, bread, cheese, and to eat grains, greens and root vegetables. Within two weeks his ulcer had gone. So I threw out the contents of my fridge.

"I follow a grain-based diet which releases lots of energy into the body. I also eat vegetables, fruits, nuts, seeds, seaweeds, beans, tofu and sauerkraut and homemade pickles. I don't eat meat or anything with additives. I occasionally have fish. Eating this way has stabilised my body. I feel better able to cope with life. I don't have a build- up of toxins in my body, so I never get itchy skin, sneezes or pimples.

"Being macrobiotic doesn't stop me having a good time. I can eat in Japanese, Chinese, Greek and Turkish restaurants, and go into any Italian for pasta and a salad."

Daily diet

Breakfast: Green tea, steamed dark greens, nori seaweed, bowl of porridge oats or steamed sourdough bread

Mid-morning snack: Water, tea, or some "three-vegetable" soup, wakame miso (wakame seaweed and miso)

Lunch: Wholewheat pasta with sauce of parsley, tahini, lemon juice and soy sauce, organic, naturally fermented sauerkraut, fried tofu with curly kale, grated carrot, chunk of cucumber

Dinner: Barley stew with onions, swede, ginger root, broccoli, blanched red radish with rice vinegar, lentil pate on rice cakes, watercress and lettuce, cooked apples with cinnamon and ground almonds, water or tea

Nutritionist's comments

With a macrobiotic diet you are eating a lot of unrefined food, which is good. But you have to be careful to get the balance right. Anna seems to do this. Miso and seaweed provide B12 and she gets protein from lentil pate on rice cakes. Beans and grain together are the ideal combination.

But her diet could be lacking in calcium. She is approaching the menopause and is more at risk of osteoporosis. She needs calcium for bone health, and has no dairy products. However, she will get some from her greens and fish.

Tom Calthrop, 27, is a vegan and computer journalist

"As a child I'd eaten anything and everything. But at 16 I suddenly became aware of all these important issues surrounding food and animal products.

"I eat no meat, fish or dairy products. Nor will I eat things that are produced by animals, like eggs or honey. I have tea and coffee and I do drink alcohol, but selectively, because a lot of alcohol has animal products in. There are fish bones in some bitters and blood in cider.

"Although I became a vegan for reasons connected with animal welfare, I soon realised that health was also an issue. Over the past 11 years I've only had two colds, and though I don't take regular exercise I'm very fit. When I was young I got horrible hangovers, but now I don't because there are no toxins inside me.

"I don't have a problem eating out. There are more than 100 vegan restaurants in London. Most small towns have at least one vegan restaurant. I can even go into Pizza Hut because its bases are vegan."

Daily diet

Breakfast: Bran cereal with sliced banana, soya milk. Tea with soya milk

Lunch: Nut roast with cashews, boiled potatoes, peas, corn (all organic), tomato, herb and onion sauce. Apple, orange juice

Mid-afternoon: Tea, soya milk, handful of almonds

Dinner: Chilli with mixed organic vegetables, kidney beans, rice, bread and vegan margarine, fruit, herbal tea with lemon

Nutritionist's comments

Nutrients that tend to be low in a vegan diet are vitamin D, B12 and riboflavin, a B vitamin usually found in animal products. One way of boosting these would be to use fortified cereals, but because Tom avoids additives he is unlikely to buy these. However, he eats nuts, which contain riboflavin.

Tom won't have problems with a lack of protein, because he's eating nut roasts and beans. People who follow well-balanced vegan diets have lower rates of coronary heart disease. Because Tom has no saturated fats from animal products he probably has a lower blood cholesterol level. This means he'll never have a weight problem, and statistically is less at risk from heart disease, diabetes and certain types of cancer.

Nutritionist's comments by Penny Hunking, a nutritional consultant.

Fresh: the Fruitarian & Raw Energy Support and Help network. Send large SAE to Hales, Heath Cross, Whitestone, Exeter EX4 2HL.

The Vegan Society: send SAE to Donald Watson House, 7 Battle Road, St Leonard's-on-Sea, East Sussex TN37 7AA. 01424 427393