IN AN age when obesity is on the rise and we're all under pressure to slim down, the diet industry has never been bigger.

The Atkins diet is currently the weight loss program of choice. Thousands of slimmers are following the lead of Hollywood stars including Jennifer Aniston, Catherine Zeta Jones, Renee Zellweger and Demi Moore, who have adopted Dr Robert Atkins' high-fat/low carb regime to retain their slender figures.

Indeed, Dr Atkins' book is the second most popular read in Britain after the latest Harry Potter and the updated edition is selling more than 120,000 copies a month.

But it is not the first diet craze to hit this country - and it certainly won't be the last. We've dieted through the decades, from the Cambridge to cabbage soup, the F-Plan to food combining, and our appetite for slimming products is not abating.

Diets have waxed and waned in popularity over the last century, as the shape that women aimed for constantly changed: from the Victorian hourglass to the 1920s washboard profile, Marilyn Monroe voluptuousness to 1960s stick-thin Twiggy look. But while fad diets may work initially, with people seeing instant results, the perennial problem is keeping the weight off.

Amanda Wynne, spokeswoman for the British Dietetic Association, says many fad diets have no scientific support to prove they work or that they are healthy.

Moreover, she argues, people will simply not stick to many of the regimes after their initial weight loss.

"Meal replacement diets, for example, are all faddy and the problem is that they are all very short-term solutions, as you have a strange drink or food to replace a balanced meal.

"Realistically, how long are you going to stick to it for? Detox diets are quite popular now, where you virtually fast for a week to get rid of all the toxins in your body. But there's no evidence that by starving yourself you will get rid of all the toxins. What you are doing is starving yourself of all the nutrients you need.

"There's no getting away from the energy balance equation - consuming and expending.

"People need to make changes to their lifestyle, watch their portion sizes, eat less, have more fruit and veg and watch their fat intake. Critically, they need to do more exercise."

So why do some diets catch on?

It's all down to marketing, according to nutrition scientist Dr Frankie Phillips, of the British Nutrition Foundation.

If you are really serious about losing weight, the best way is to do it slowly and steadily.

The Hay Diet: This food combining diet was created by Dr William Hay in the early 1900s, based on the idea that the body can't cope with proteins and carbohydrates at the same time. It became popular again in the 1990s. You should eat 60 per cent fresh fruits and veg, as much as possible in their raw state. The remaining foods should be proteins or starches that shouldn't be eaten together.

The Cambridge Diet: Developed by a research scientist at Cambridge University in the late 60s. Described as a nutritionally complete formula food providing 100 per cent of the Recommended Daily Allowance of all vitamins, minerals and trace elements, it involves having a number of sweet drinks or soups instead of a meal. Mousses and meal bars have also been developed. It has reportedly helped more than 15 million people lose weight.

Weightwatchers: Devised by housewife Jean Nidetch in 1963, it is designed to provide a balanced diet and is big on watching calories and fat content, as well as measuring exact quantities. You are allowed so many points a day and each food holds a certain number of points. Members are also weighed each week. It is generally seen as one of the more sensible diets on the market.

The Atkins Diet: First introduced in 1972, it allowed dieters to eat all the fatty foods they loved. High in fat and low in carbohydrates, you can eat as much meat, fish and chicken as you like, plus bacon, eggs and cheese. But you have to cut out carbohydrates - bread, potatoes, pasta or fruit. Its popularity waned in the 80s but the endorsement by A-list celebrities in the 90s sent it soaring again with Dr Atkins' New Diet Cookbook. Some nutritionists have claimed that a regime so high in fat and protein and low in anti-oxidants could cause health trouble in the long term, leading to brittle bones and damage to kidneys and liver. Users admit side effects such as constipation and bad breath.

The F-Plan Diet: Created by Audrey Eyton, this was popular in the 80s and promoted carbohydrates, raising the profile of baked potatoes enormously. The idea was that fibre fills the stomach and reduces the desire to overeat. The book, The F-Plan Diet, was published in 1982.

Rosemary Conley Low-Fat Diet Plan: The TV diet and fitness expert discovered a diet plan she said transformed her body. She put her experiences on paper and came up with her Hip And Thigh Diet, published in 1988, which sold two million copies.

The Cabbage Soup Diet:

Allegedly created in the 90s for patients recovering from surgery, it involves eating as much cabbage-based soup as you want for about a week. Dieters can eat a limited number of other things as well, including fruit and vegetables. But critics say that as cabbage has no fat-burning properties, most people just lose water.

Updated: 09:05 Thursday, August 07, 2003