Rosemary Conley's Hip and Thigh Diet was launched 10 years ago and has sold two and a half million copies. The author herself unabashedly uses words like "phenomenal" and "amazing" to describe her idea and has even had a vote of thanks from the Archbishop of Canterbury.
Such is her success that in 1993 the Rosemary Conley Diet and Fitness Clubs were launched across the UK operating under a franchise system. There are now more than 2,300 classes a week with 70,000 members. The classes are run by 170 franchisees, who have each paid pounds 12,000 for use of the Conley name and for training and kit. Ms Conley also receives pounds 11 for each class that is held.
"IT'S VERY easy to make the assumption: `Oh, that's a nice little number', but we make a very small profit," she insists. "It's completely inappropriate to say we make pounds 23,000 a week on it. We make a profit of only about 10 per cent and this year, because there's been so much investment, we won't make even that."
Still, her achievements mean she can now afford to live in a manor house near Melton Mowbray. It's a far cry from when she was born 51 years ago to Celia (an entrepreneurial housewife who invented a nylon cap to go over hair rollers which she sold to Harrods) and to Oswald, a hosiery wholesaler.
Ms Conley says it was a difficult time: her father had been away through the war, leaving her mother with a six-week-old baby (Rosemary's brother). Rosemary herself suffered chronic eczema as a baby and developed asthma. "They didn't think I'd see my 10th birthday."
When she was 14 they moved from the countryside to the city of Leicester. Rosemary didn't like her new school and left before her 15th birthday to do a secretarial course. She met her first husband, Phil, when she was 16, married him at 21, and had a daughter, Dawn. It was when she married that her weight problem began. She took herself off to Weight Watchers, but then decided to start her own class in her kitchen.
SAGG (Slimming and Good Grooming) grew into a chain of slimming clubs which she sold to IPC in the early 1980s for pounds 50,000. The money allowed her to part amicably from Phil who, friends say, was never as ambitious as her (in her twenties a frequently voiced ambition was to get a Jag; she later got one with the numberplate ROS1E). Ms Conley will only say of the break-up: "We had changed. I had not had a career when we met. We went our separate ways, but we remain good pals."
Then, in 1986, two events changed her life: she got gallstones and she got God. She's seen a link between them ever since. Her doctors told her that if she was to avoid surgery she would have to go on a low-fat diet and take more exercise. She did, losing weight from her hips and thighs in the process, and then decided to write about her experiences.
While in hospital Ms Conley saw an advertisement for a Christian book called The Power of Living. She sent away for it, and it changed her life, she says. She now thinks her conversion was responsible for the success that followed: "When I gave my life to the Lord it was like having a new chairman of the board making the decisions, someone who had your best interests at heart."
Emboldened by this she proposed to her second husband, Mike Rimmington, who is 13 years her junior (she hates people mentioning the age difference) and works with her in the sprawling empire that is the Rosemary Conley Group. It includes her own magazine, videos and fit-ness clubs, as well as her many media commitments.
But what every woman needs to know is: does her diet work? Ms Conley is not without her sceptics. While few dieticians would disagree that lowering your fat intake and increasing exercise will help you lose weight, they are more cautious about Conley's promise to see inches fall off your thighs and hips. John Garrow, Professor of Nutrition at St Bartholomew's Hospital, London, says: "The title implies that the diet can specifically reduce fat from the hips and thighs; but no diet can do that. I think she's got a good title but you can't spot-reduce fat."
Ms Conley now says she is not promising the earth: "I'm not saying you can spot-reduce fat but if you go on the diet you do lose the fattiest parts, not the lean muscly bits." When challenged, she mentions that she was asked to address the Association for the Study of Obesity last year and is having a paper published in its international journal this year.
What is the secret of her success? Where the likes of Jane Fonda and Elle Macpherson have traded on their stardom in producing diet and fitness books, Ms Conley has made a virtue of her lack of celebrity. "Women feel I'm one of them. I have to watch my weight and be careful over Christmas," she says. And she knows what it's like to be fat, to eat five litres of ice-cream at a sitting and to smear cheese with butter. From the start she was neither stunningly beautiful nor anorexically thin. She was Mrs Average who, by a combination of a good idea and hard work, has transformed herself.
On the surface the diet industry and religion have much in common - both demand self-discipline, both promise future happiness if you adhere to certain precepts, both attract women more than men. Conley's whole business is wrapped in the language of evangelism. At the beginning of every hip and thigh diet are testimonies to the way people's lives have changed. Audrey Bewley wrote to her: "I have been following your diet, and every word is true."
Pam Irvine wrote: "Never have I lost so much so easily and quickly! I feel 100 per cent better in myself."
Ms Conley once said: "I am the Delia Smith of the diet world. I am reliable, I am steadfast, I deliver." Apart from their omnipresence in their fields, and their ability to attract the aspirational middle-classes, both Delia (who is a Catholic) and Rosemary get strong support from the Christian community.
Paul Handley, editor of the Church Times, says he has witnessed fanatical support for Christian celebrities. "It could be called the ghetto approach, which is: `Oh, Gosh! Someone famous has become a Christian. That makes us slightly more important.' Also, people won't criticise a fellow Christian; they are predisposed to see them in a good light and are more likely to buy their videos, records and tapes."
CONLEY herself claims she hasn't received unequivocal support from the Christian community. "There are people who think it's terrific. I once got a tremendous letter from the Archbishop of Canterbury when he was Bishop of Bath, saying he'd been on my diet. On the other hand I'll get misquoted in the press."
The real success lies in the title of her book, which feeds on every woman's neurosis about her figure. Conley says she took six months trying to think of a clever title. In desperation she thought: "It slims hips and thighs, so that's what I'll call it."
Ten years on, she hopes to develop her own range of foods with Marks & Spencer, have a Rosemary Conley club in every neighbourhood, and expand her television work. Rosemary Conley, the new religion, will be everywhere. But as she promotes a faith which claims to love everyone as they are, does she ever wonder whether what she is doing is right? "The pressure on women to be slim - that's not my fault," she insists. "I'm not trying to make us into a nation of stick-thin people. Just because lots of people are making a bad job of it doesn't mean someone can't do a good job. I see what I do in the same light as an anti-smoking campaign - making people healthier."