What's the story with diets?

The Happy diet and the Eat All Day diet are just two of at least a dozen new weight-loss programmes the glossy magazines in your local newsagents promise will lead to a thinner, happier you before springtime. Without actually opening any of these magazines, it's safe to assume that the diets carried within will never actually deliver a leaner you. Quite apart from the fact that any programme calling itself the Eat All Day diet seems doomed to failure, survey after survey has shown that the vast majority - between 90 and 95 per cent - of diets fail.

Despite this abysmal success rate many people still take such programmes seriously and spend serious amounts of time, emotion and money on diets ranging from the almost sensible to the entirely nonsensical. There are currently more than 10,000 diet books for sale on amazon.com and the diet industry in the US alone is worth in excess of €50 billion annually.

Figures for Ireland are harder to come by but even the most casual look at bookshop shelves which groan under the weight of the diet books they hold would suggest that our appetite for the quick-fix diet is equally insatiable.

There are books, courses, television programmes, websites and, increasingly, surgical procedures all aimed at helping people to slim. Then there is the proliferation of ridiculous detox programmes currently selling for in excess of €50 a time.

Critics believe the diet industry is more about exploitation than helping people lose weight. Margot Brennan of the Irish Nutrition and Dietetic Institute (INDI), which represents the majority of qualified dieticians in the Republic, is just one vociferous critic of the diet industry.

She recently reviewed 12 diet books for a television programme and found virtually all of them to be useless. "The diet industry is one of the few industries that flourishes on failure," she says. "It has to. People try one diet and when it doesn't work they move on to the next one. I know some very intelligent women who have bookshelves filled with diet books and they simply do not work." When celebrities with personal trainers, lifestyle gurus and nutritionists on 24-hour stand-by constantly move from faddy diet to faddy diet and still struggle to shed and keep the pounds off, what chance do the rest of us have? None at all, according to Brennan. "These fad diets do not work, it is as simple as that." She says that if people are concerned about their weight they should consult a qualified nutritionist or dietician. "It is more about eating healthily and changing one or two things a week instead of going on some crash diet and changing everything about the way you eat overnight."

Brennan says that while losing weight has enormous health benefits for people who are overweight, those benefits evaporate if the weight loss is done wrong. "If you go on the cabbage soup diet for two weeks you will lose weight, certainly, but you are also cutting out an awful lot of essential nutrients from your diet and you will not be able to sustain the weight loss." She dismisses the controversial low-carbohydrate Atkins Diet, as "rubbish" while some of the other prominent faces in the dieting world are, she believes, "not qualified to say anything about nutrition".

One person who would seem less than fully qualified to help people lose weight is Jade Goody. Prior to her unfortunate return to the Big Brother arena where she first made her gobby name, she released a DVD entitled Jade's Shape Challenge. In the DVD, which costs in excess of €20, Goody explained how she had shed two stone in 10 weeks through a strict diet and fitness regime.

Then, just as her career was going into meltdown inside the house, allegations emerged in the tabloid press that she had not followed the fitness and healthy eating route she was advocating but had spent €7,000 on liposuction. The impact the story has had on sales of the DVD have yet to be established.

Medical procedures, whether liposuction or stomach stapling, are becoming more common for people desperate to lose weight. Stomach stapling is the fastest growing surgical procedure in the US and more than 140,000 people elected to undergo it last year.

Brennan believes it will not be long before it becomes as widespread here with private clinics offering the service. It is costly, life altering and has risks. While it should be viewed as a last resort, it is becoming another quick fix for people who are moderately overweight.

Although you can lose a substantial amount of weight on short-term crash diets, it is very unlikely the weight loss will be sustainable and you will almost certainly end up putting on even more weight, the INDI says. Studies suggest that the more crash diets people go on, the more weight they actually gain as repeated crash dieting slows down the body's metabolism. The INDI suggests people look for small, simple changes that will give slower results, but will last longer. "In the end you will lose more weight and, even better, you will be able to keep it off." In the early 1990s the US-based National Institutes of Health (NIH) Technology Conference published a list of recommendations for consumers considering weight loss programs. They still hold up today. "In evaluating a weight loss method or program, one should not be distracted by anecdotal 'success' stories, or by advertising claims," it cautioned.

It suggested that before embarking on any programme, consumers should find out the percentage of all participants who completed it, the percentage who had achieved various degrees of weight loss and the proportion of that weight loss that was maintained at one, three, and five years.

In addition it said the number of participants who experienced negative medical effects should also be established. One suspects that if this criteria was applied with rigour by all dieters, the industry as we know it would collapse overnight.

Health Supplement tomorrow: Sylvia Thompson provides a guide to what's in and what's out in the world of dieting