For 35 years, Rosemary Conley has reigned supreme as the queen of slimmers. She tells Women's Editor Sarah Foster the secrets of her success - and what she thinks of Victoria Beckham.

MY first question sends Rosemary Conley into peals of laughter. "I've read on the Internet that you're 49.

Is that right?" "That's hilarious, " she chimes. "I'll be 60 in December.

I've said that if anybody sends me a birthday card it mustn't have 60 on it, otherwise it's going in the bin." Then on a more positive note: "Sixty is the new 40."

As head of a multi-million pound exercise and slimming business, Rosemary certainly has cause to smile. The Hip and Thigh Diet which made her name is still a staple of her regime and every week it's taught at clubs throughout the country by her franchisees. Following the success of her first book, published in 1988, Rosemary has gone on to write 26 more, as well as starring in 27 videos. Not bad for someone who just wanted to lose a few pounds.

It all started at her home in Leicestershire where, newly married to her first husband, she saw her figure expand. "I first put on weight when I first got married when I was 21, " she says. "I gained two-and-a-half stones, going from eight stones to about ten stones four, which for me, was really big as I'm only five feet two."

So what was she doing wrong? Rosemary says hers was a common case. "I was just binge eating and I really had a bad relationship with food, " she says. "I found it really difficult to manage my passion for eating certain foods. I loved ice cream and I loved eating anything with butter on it. I loved cereal, toast and marmalade - those sorts of instant things that could be quite sweet."

Deciding to take things in hand, she began to diet - although it took a health scare for her to really reform. "Initially it was learning that if I carried on like that, I was going to carry on gaining more and more weight, " says Rosemary. "It did come off but then I had gallstones and went on a low fat diet. That completely transformed my eating because I realised I could eat well and as long as it was low fat, I could keep the weight off."

Prior to this discovery, she'd already run slimming clubs, having started out with a small class in her village hall. More clubs followed, and then a partnership with magazine publisher IPC. When this ended, Rosemary went freelance - and after the gallstones, devised the Hip and Thigh Diet.

"When I put it out, the results with everybody else were just as astonishing as with me, " she says. "I wrote about it and it was a huge international bestseller. It sold two million copies."

REFRESHINGLY open and down-to-earth, she admits her approach is common sense.

"Eat less, do more. It's not rocket science, " says Rosemary. "Fat contains twice as many calories as other food so if you cut back on it, you're cutting back on very high calorie food. Also fat is very easily stored in the body and not easily spent.

You have to start burning fat from your body. The more exercise you do, the more calories you burn and the more weight you lose."

What's unique about Rosemary's classes is that along with diet tips, there's a full workout. She takes her role as their figurehead extremely seriously. "Our instructors are just the best - they're all carefully selected and I meet every single one of them, " she says. "We are very selective as to who we take on board because they're going to represent my name. We teach them to teach exercise to music and they also take a nutritional qualification with us. Dr Susan Jebb is our nutrition consultant and she basically checks the diets to make sure that everything is absolutely spot on."

And what about Rosemary herself ? Is she the model eater we might expect? She claims not.

"There have been times when I've found a few pounds creeping on, " she admits. "For me the pressure is on because I can't be seen to be gaining weight so I have to be quite strict with myself. I do keep a fairly careful eye on it but I tend not to weigh myself very often - I know from my clothes what my weight is. I wouldn't say I go off the wagon and have a binge but it doesn't mean I won't occasionally have a treat. If it's somebody's birthday I'll have a cream cake and thoroughly enjoy it."

Rosemary's secret to staying slim is quite simple: eat sensibly most of the time and when you fail to, don't beat yourself up. "For me, the big problem is if you're going and speaking at various dinners and you have a big three course meal and you have three in a week, but if I do, I'll just cut back a bit, " she says. Neither would she admonish struggling club members. "We would always be totally lenient with them, " she says. "We would say 'let's get back on the diet this week and I'm sure you'll lose most of the weight'."

At the root of Rosemary's life, and what sustains her efforts, is her strong aversion to being fat. "Having been paranoid about food for many years I'm now absolutely determined not to be, " she says. "I love being slim and I hate being overweight. The phrase 'nothing tastes as good as being slim feels' came from our classes. It was a line that was pinched by (the TV series) Fat Friends."

But what about when dieting goes too far, spiralling into something unhealthy? I wonder if Rosemary has experienced this. "I was a failed bulimic. I remember trying to make myself sick and I couldn't, " she jokes. Becoming more serious, she says: "I think it's sad that people aspire to look like people who are stick thin because it's not attractive. Often girls see themselves as slim when in fact they're grossly underweight and that's a real shame. We should look towards being a healthy, fit weight."

Yet with people like Victoria Beckham in magazines, it's no surprise that being skinny is seen as chic. Does Rosemary blame such svelte celebrities? "I wouldn't point the finger, " she says magnanimously. "I think they (David and Victoria) are a great couple. Posh has gone through her own problems in her life, which no doubt have caused her a lot of stress. I don't think she's ultra thin because she wants to set an example to other people."

At the other end of the scale, Rosemary is concerned about the rise in obesity. "It used to be that eating disorders were a major crisis whereas now, obesity is a major crisis with children, " she says.

"It's all about understanding what is a healthy weight, that exercise is something we should be doing more of, and about eating a low fat diet. I was in Austria recently and they label everything with how much fat content there is and I think that's terrific."

While she's sceptical of fads, in an ever-changing industry, Rosemary must move with the times. Her latest innovation - and one she's enthused by - is adopting the GI diet. "GI is a very healthy way to eat and it's generally accepted by the medical profession that eating a low GI diet is good, " she says. "I've cut through all the complications and tried to make it simple. Basically, foods with a low Glycaemic Index allow your blood sugar to be released more gradually than foods with a high GI rating. A low GI diet makes you feel full for longer. We've been using it in our classes and in the 13 years of clubs, we've never had results like it."

Next for Rosemary is another book - the sequel to her GI Jeans Diet - a new video and more items for her nascent food range. "We've got three products already - a Belgian chocolate mousse, low fat ice cream and a low GI nutrition bar, " she explains. She may be almost 60, but she shows no signs of slowing down. "I love doing what I do and I really will carry on for a long time yet, " she says. "I can see me doing this when I'm 80."

Rosemary Conley's GI Jeans Diet (Arrow, £6.99).

Rosemary is currently looking for North-East franchisees to run classes. To find out more, contact Heather Shaw on (01509) 622000 or email Heather.Shaw@rosemary-conley. co. uk. To join a class, call (01509) 620222 or visit www. rosemary-conley. co. uk