Matters of the heart Since chef James Martin danced off three stone in four months, he's never felt better - and he has good reason to keep it off, finds Cate Devine

"Before I lost weight, I was always self-conscious about how I looked. When I watch back episodes of Ready Steady Cook, I think: 'Oh my god, I'm quite big.' And when I started on Strictly Come Dancing, the outfits made me very aware of my size. They were extremely tight."

It has to be said that James's weight-loss regime was slightly more intense than most. His training as a contestant on BBC1's Strictly Come Dancing started in September and lasted until December when he reached the semi-finals. This meant that, along with other contestants DJ Zoe Ball, cricketer Darren Gough and athlete Colin Jackson, he was exercising for eight hours a day, five days a week, for four months.

"It was very different from the running around you do in a kitchen, especially because the costumes were so tight, " he says, as a make-up artist dabs foundation on to his flawless skin for the cameras. "It was more difficult for me than for other contestants like Darren and Colin, because they were more used to it. I found it absolutely exhausting."

All that stopped with the end of the series just before Christmas, but he's about to order a new set of chef's whites in a 42in chest because his old 48in ones are too big. Clearly, he's managed that most Herculean of tasks - keeping the weight off. "Maintaining the loss was extremely difficult, and I was really in danger of piling it back on, " says the 34-year-old bachelor. "A chef's diet is notoriously bad, despite the lovely food you're preparing for other people all day. We tend to cram in calories on the hoof, and at the end of a long day the last thing you feel like is going home and cooking a proper meal for yourself."

Staying slim and healthy was vital for James, and not just because of his busy, high-profile TV career. As well as being an anchor on Ready Steady Cook and regular guest on chat shows such as Richard and Judy, he is also much sought-after by print media and is due to feature in the May issue of Cosmopolitan magazine.

Yet he had a much more serious reason for looking after himself - the male line in his family is plagued with heart problems. His late paternal grandfather died of heart disease, and his father, formerly the resident chef of Castle Howard in Yorkshire, has already suffered three heart attacks. James saw his dramatic weight loss as a chance to break the pattern.

"Heart disease has been an issue in my family for generations, " he says. "My dad likes his food deep-fried with lots of butter but he doesn't like running it off. I don't do much exercise either. When you're a big bloke like my grandfather, father and me, it's not as easy to stay fit as it is for someone who's a bit smaller.

"So I decided to examine my diet and I made a conscious decision to cook fresh food at home. I no longer stuff my face with really bad things such as takeaway pizza, Mars bars and fizzy soft drinks, which I used to have tons of during my working day, just like almost every other chef in the country. Now I eat fish twice a week as well as loads of vegetables and fresh fruit." He has also started using a pedometer in the kitchen, and regularly clocks up 16 miles a day.

To further emphasise his new-found commitment to maintain a healthy heart, James is fronting a nationwide campaign whose aim is to encourage all of us to eat more omega-3 fatty acids in the form of at least one portion of oily fish every week.

Sports presenter Gabby Logan and chefs Rick Stein, Brian Turner and Nick Nairn have also joined him. Heart disease is the leading cause of death in Scotland and the rest of Britain. "The reason I chose to front this heart health campaign is that it has a personal dimension for me, " he says. "One of the sad things is that heart disease is actually preventable, and yet nearly 2.5 million people have it and 120,000 of us die of it every year. This is because, despite cheap travel to European countries, we are still a nation of animal fat-loving people. We might admire the Mediterranean diet but we don't eat the way the French, Spanish or Italians eat. On holiday, we insist on going to restaurants that serve the full British breakfast, and at home we just slather on the butter and eat far too many processed foods."

The heart health campaign recommends just one portion of oily fish a week. "Six ounces or 140g a week isn't a massive amount, " James says. "Yet 70-per cent of us don't eat fish at all - and that figure is worse in Scotland, even though you're surrounded by the sea. It's absolutely crazy."

Does he think that healthy eating has become the preserve of the middle classes? "No, absolutely not, " he says. "You only have to walk around the supermarket to see stuff that you didn't see 10 years ago. It used to be that lemongrass was only for one type of person, now it's available to everybody, and at affordable prices.

"To say that good food is elitist is just tosh. Good food is simply cooked food - it's not rocket science. You don't have to be a Gordon Ramsay to cook yourself a healthy meal. What could be simpler than pan-frying a little bit of salmon and serving it with some great new potatoes and seasonal veg?"

Eating to prevent heart disease is not all about lettuce and tomatoes; it's about getting a balance. "A good healthy diet is a combination of fruit, vegetables, meat and fish, and with exercise you'll keep the weight off, " James says. He's on a roll now. "I really believe that most of the problems surrounding what we eat - such as bird flu, mad cow and foot-and-mouth disease - are because we humans delve too much into the science of food when we should be concentrating on the past and all that is great about our agricultural heritage. "I think we're messing around too much with our food. We've gone from being a nation of farmers to a nation of food scares. We should be asking why that has happened."

He won't be doing another Strictly Come Dancing because he has too much else on his plate. Later this year he will open his own cookery school at his converted barn in Hampshire, which backs on to a four-acre vegetable plot. He will produce all the food for the school, and the process of building his greenhouse then growing, cooking, eating and selling his produce will be the subject of a new television series that has just been commissioned by UKTV. James has also just launched his own TV production company which, like the series, has no name as yet.

He publishes his fifth cookbook, Winter Food, later this year, and he is currently filming two episodes of Ready Steady Cook every other day. With all this going on, it's tempting to believe that the life of a telegenic celeb chef prevents him from doing much cooking at all. After all, his life has changed dramatically from the early days toiling in the hot and steamy Michelin-starred kitchens of Marco Pierre White and Brian Turner, having been first talent-spotted at the age of 18 by award-winning chef Antony Worrall Thompson. James was head chef of his own restaurant in Winchester at the age of 21 and first appeared on television at 23. He now runs the restaurant of P&O's new cruise ship, Ocean Village.

"It's been a rollercoaster ride for 10 years and it's all kicked off again since Strictly Come Dancing, " he says. "I do cook quite a lot, although it's mostly test-cooking for myself and the cruise ship."

Does he think his good looks have helped his TV career? "At the end of the day, whether you can cook or you can't just comes through, "he says. "Some people rely on their looks to get them on telly, but it soon shows if you can't hack it. I've been doing TV for 10 years. I can't help the way I look, but I'm confident that I can cook."