Mary Evans Young, a management consultant and psychotherapist, says that Britain is in the grip of a dieting 'epidemic'. Yet despite the fact that 90 per cent of women and girls will diet at some point in their lives, for the overwhelming majority of them - 95 per cent - the diets will not work. Within two to five years, all the weight lost, and more, will have been regained.
'Together with the media and fashion industry, the powerful diet food industry has artificially created a 'problem' which has resulted in the vast majority of women in Britain and other Western developed countries feeling that they need to diet,' Ms Young says in Consumer Voice, the journal of the National Consumer Council.
Ms Young founded Diet Breakers last year after her work with women executives showed that they were spending more time worrying about their diets and appearance than their career development.
She was also prompted by the case of a 15-year-old girl who committed suicide because she was size 14, and by publicity on women who had their stomachs stapled.
Diet Breakers is a national voluntary campaign which funds itself through anti-dieting workshops. Since its launch, more than 4,000 women and 100 men have written seeking help.
On 5 May, along with groups in the United States, Canada, Australia and New Zealand, it will organise the second annual International No Diet Day.
Ms Young says that if dieting was regarded as a product, most dieters would demand their money back. Girls as young as eight are under pressure to be 'abnormally thin'. At any one time, half of British females are on a diet. 'We're a failure if we're not thin (and) . . . we feel a double failure if we diet unsuccessfully. The idea that it's the diet that doesn't work never crosses our minds.'
Most women who diet are not obese and only want to lose 10lb or less, she says. Insurance companies only consider a person a health risk if they are four stones above their recommended weight. The health risks of dieting - which are rarely made clear by companies - include gall stones, constipation, heart stress, infertility, depression and mood swings.
Diet Breakers wants trading standards officers to prosecute the pounds 850m dieting industry. Current targets include plastic pants to increase fluid loss, skin patches that purport to speed up the metabolic rate, 'Choc- Aroma' sniffing sachets which are claimed to control chocolate addiction and a book, Size 12 in 21 Days, published by Ebury Press.
Ms Young said: 'The average woman in this country is size 16. If you managed to get to size 12 in 21 days you would be undermining your health.'
A spokeswoman for Ebury said it would be 'extremely dangerous' for a 20-stone woman to slim so fast, but it would be silly to interpret the title literally.
She added: 'There is a market out there for people who do want to lose weight quickly, but you will put it back on again unless you eat sensibly for the rest of your life.'
The spokeswoman said the company was also publishing the Eat for Life diet based on findings from the World Health Organisation.