So, is fat back?

It can take a long time for innovative ideas to be accepted by the medical establishment, especially in the field of nutrition, as Dr Robert Atkins, author of The New Diet Revolution, well knows.

His best-selling diet book, which advocates the unlikely theory that eating fat doesn't necessarily make you fat, is now at the top of the London best-sellers list - but for most of the past 30 years since the book was first published, he has been mocked by doctors and dieticians who felt his work was nutritional heresy.

How could eating steak, with its high content of saturated fat, possibly be good for your health? Surely, it helped raise cholesterol levels and contributed towards the risk of heart attacks? The virtues of the low-fat, high-carbohydrate diet became the accepted wisdom by the late 1970s, and has been with us ever since.

But now, new research has revealed extraordinary results which back up Atkins's theories that, actually, carbohydrates are the bad guys.

Here, one man explains how learning to love the fat in his diet changed his body shape for the better - and even lowered his cholesterol levels.

Stefan's story

Stefan de Silva, 30, is a personal trainer. He lives in south-east London.

For years, I couldn't understand where I was going wrong with my diet. Ever since I was 16, when my father had had a triple heart-bypass operation, I had known I'd had high cholesterol levels. His doctors advised that, like him, I should follow a low-fat diet, with plenty of carbohydrates.

On paper, it looked absolutely right, but soon after I began the low-fat regime, I put on lots of weight. I've always done lots of exercise, so it wasn't that I was being idle; but I just couldn't seem to get things right. I'd have a bowl of cereal and a couple of pieces of toast for breakfast; sandwiches or a bowl of pasta for lunch, and in the evening, Mum would make sure that she'd stripped all the fat off the meat she was cooking, and would serve up lots of carbohydrates such as rice. I ate a lot, but I would always get cravings. I never had that feeling of being full. I could eat carbohydrates until the cows came home - a whole box of cereal at a go - but it didn't do a thing for me, in terms of satisfying my appetite. I suffered from water-retention, digestive problems, and despite all the exercise I was taking, I felt lethargic.

When I had my cholesterol levels measured aged 18, they were really high - about 6.5mmol/L. I couldn't understand it. I exercised harder; I watched what I ate, but I'd look around me in the gym and wonder where I was going wrong. I was eating right, working out; why wasn't I getting the results?

But I was living the sort of life that I thought I had to, so I carried on like this for years. I became a personal trainer when I was 24, and didn't battle with my weight - it had gone up from 80kg (12 stone) when I was 16 to about 117kg (17 stone), but I'm 6ft 4in, and train heavily, but it was frustrating because, whatever I did, there was no positive change in my life.

The turning point came when I heard about the theory of "metabolic typing", which works out which foods you need to eat in order to balance your underlying body biochemistry.

It made a whole lot of sense to me. It's not a diet so much as a paradigm. We're all different, and thus, people have different nutritional requirements.

If you go into any bookshop, there are 101 different diet books, and the one thing that holds true for all of them is that they've all worked for a few people, however different the theories are. Working backwards from that, it makes sense to work out what kind of person you are, diet-wise, rather than trying to adapt your body to the prevailing medical theory.

Once you can understand that, then you can begin to explain why some people can lose weight on a highfat diet, while others will lose weight on a high-carbohydrate diet. I found a nutritionist, Alison Loftus, who could put me through metabolic typing tests. The tests aren't too complex - you can get a kit to do them at home - and what they showed was that I was predominantly a protein and fat sort of person, and that I scarcely need any carbohydrate at all. Since then, I've been fine-tuning what I eat.

It's a big change, but a great change. Now, at last, I can eat food that really satisfies me. My appetite has dropped and as a result, I don't actually eat as much as I used to, but I certainly don't feel hungry. I feel full a lot quicker, as well. In terms of calories - I'm probably not taking in any less, but then I simply haven't needed to work it off. When you start eating the right foods for your body type, you can still lose weight even if you are consuming more calories than before. The idea that you simply have to drop calories to lose weight is rubbish.

At Alison's suggestion, I began to eat completely differently. She gave me a tailor-made programme. I'll start with eggs and bacon for breakfast, then have something like a seafood mayonnaise salad for lunch, and a large steak with a vegetable stir-fry for dinner, with cheese and nuts for snacks. It might sound mad, but it had startling results straightaway. At first, I dropped a lot of the water I had been retaining, and so I stopped looking bloated. I have more energy, and I have lost weight - from a top weight of 117kg, I'm now about 110kg (16 stone).

My body has changed, too - my training is showing proper results, and I have much more muscle mass. I feel sharper have a faster recovery rate, and my allround performance has improved. The final bonus has been that my cholesterol levels have fallen rapidly, from 6.1mmol last autumn, to 5.4mmol.

It has proved to me there is little link between ingested fat and body fat.

My friends are a bit taken aback to see me piling into all this high-fat food. "Are you sure you want to eat that?" they ask.

For me, it's a lifestyle, not a diet; it's the way my body needs to eat to be healthy.

Alison Loftus, Hale Clinic: 0870 167 6667.
Stefan de Silva, Total Trainers: 07944 122 198.