Low-fat food may not be low in calories... and with added sugar they won't always improve your diet, warns Sarah Edghill
Last month saw a food phenomenon introduced into selected supermarkets: Enter Entenmann's gooey, irresistible cakes and pastries. Danish slices in a variety of flavours, a chocolate fudge brownie that melts in the mouth. Yum yum.

Automatically contemplating your waistline and chewing your nails? Entenmann's suggests it has bypassed the guilt zone. Tthe front of its packages carry the legend: "97 per cent fat-free". Sales targets have gone through the roof.

In one branch of Tesco, shoppers are loading Entenmann's into their trolleys, certain that they can have their cake and eat it. One woman says she's buying cake for a husband "with high cholesterol". An elderly couple are looking for a "treat", but don't "want to feel too guilty about it". A young mother waxes poetic: "When I first saw the label that said 97 per cent fat-free, I thought, 'Healthier, but boring'. But these cakes are so good you'd never know the difference."

Low-fat food alternatives first appeared on shelves at the end of the Eighties. They have become a multimillion-pound business. Now almost every "bad" food, from chips to chocolate, has a low-fat, reduced-fat or fat-free version. For a society under constant pressure to conform to slim ideals, the low-fat thing has been seen as a godsend.

This craze started (surprise, surprise) in the United States. Fridges from Manhattan to Los Angeles are packed with low-fat cookies and muffins; sales of low-fat products total $23.5bn a year - a 5.6 per cent share of the food market.

Now low-fat fever has taken hold here, albeit in a different way. "In the US, bakery products like cakes have been very successful," says John Young of the Leatherhead Food Research Association. "But here it's the dairy sector that has taken off." Indeed. Many of us use low-fat fromage frais rather than double cream, and grate low-fat cheese over our jacket potatoes. Gold-top milk was once thought a luxury, but in 1993 sales were overtaken by skimmed and semi-skimmed.

Health worries have helped. Fat makes food taste great, but has more than twice the calories of proteins or carbohydrates. It is also known to raise cholesterol levels and be a contributory factor in heart disease, the biggest killer in Britain.

Current research also suggests that to lose weight you should switch from fats to carbohydrates. "If you get more calories than you need from fatty foods, the evidence is that these are more likely to be stored in the body than extra calories from carbohydrates, so you may put on additional weight," says Adrienne Cullum of the British Nutrition Foundation.

Not surprisingly, the marketing men are jumping on the bandwagon. Four years ago, Walls' launched Too Good To Be True, a virtually fat-free ice-cream dessert. Despite its waxy flavour, sales in the UK are worth about pounds 21m a year. Marks & Spencer has special "Lite" and reduced-fat ranges, and Tesco has a "Healthy Eating" equivalent. The Tesco foods range from low-fat oven chips to low-fat cheesecake. In July, a range of virtually fat-free soups hit the shelves. Although neither chain was prepared to say how much their low-fat ranges sold annually, both describe their impact as "significant".

Even foods naturally low in fat, such as bran cereals, are now being actively advertised as low-fat alternatives. Exotic meat such as ostrich and kangaroo is promoted as being relatively low in fat, and the Meat and Livestock Commission recently ran a series of adverts, including one saying that a pork chop contains less fat than cottage cheese.

True or false? The big problem is perception. People see the tag "low- fat" and assume a particular food is diet-friendly. But just because it contains less fat, doesn't mean it has fewer calories. McVitie's Light Digestives contain 2.4g of fat per biscuit, compared to 3.2g in normal digestives. However, there is a difference of only four calories between the two.

To make such products, fat must be left out of the manufacturing process. Sometimes water is used in its place, or fat replacements such as carbohydrate- based gums that give bulk. These are not necessarily bad for us. However, many manufacturers also increase the amount of sweet ingredients, such as sugar, jam or honey - high in calories and not good for your teeth.

A spokesperson for McVitie's admitted that a Light Digestive contains more sugar than a normal one, and Entenmann's doesn't hold back on sweeteners. "Our cakes are packed full of sugar," says the company's marketing manager, Gerry Bagnall. "We don't want to give the impression that they help with weight loss."

Manufacturers claim they don't promote such products as slimming foods, but by adding brightly coloured "Low in fat" or "Fat-free" labels, they do play on our dietary preoccupations.

"These are not slimming products, but that is how people take them," says Ms Cullum. "If something is low in fat, people see that as a licence to eat more. But low in fat doesn't mean it contains no fat. Anyway, the original product might have been exceptionally fatty, like cheese, crisps or biscuits."

Take low-fat spreads, says Ms Cullum. "Of course, they are better for you. But if you don't eat much butter anyway, switching to a spread and ignoring the rest of your diet won't do much good."

Some of the criticisms of low-fat products have concerned taste. But there have been success stories. Most low-fat cream cheese spreads are indistinguishable from the original, as are cottage cheese and many low- fat yoghurts. Even Ambrosia Low Fat Rice Pudding, with half the fat of the original, is creamy enough to satisfy most tastebuds.

"In the dairy category, it is comparatively simple, technically, to produce foods of a similar quality," says John Young of the Leatherhead Food Research Association. "It's the bakery products that present problems. Entenmann's are in the minority. However, there is potential if manufacturers find the right combination."

In our society being slim equates with attractive and successful. So foods that pile on the pounds are seen as Public Enemy Number One. What is worrying is that, on their own, low-fat foods aren't improving our health or changing our attitudes. They allow us to carry on eating things we feel we should avoid, under the misapprehension that we're doing ourselves, if not any good, at least no harm.

"These products aren't the whole answer," says Ms Cullum. "You still need a balanced diet and to eat more starchy foods, fruit and veg."

That's the problem. As a nation, we're not big on self-denial. Expect low-fat goodies to continue selling, quite literally, like hot cakes.