A big slimming-food business has grown up in recent years, aiming to capitalise on the millions of people who are too fat. Some products may be useful as substitutes for higher kilojoule foods - slimmers' drinks, for instance - but nothing you can buy will take the place of your own selfcontrol. Nothing you eat can be 'slimming' because all foods contain kilojoules. The best kind of balanced diet helps to re-educate your food habits, so you not only lose unwanted weight, but keep it off, too. Here's a guide to some of the many aids available.

Substitutes

Sweeteners Saccharin tablets are a slimmer's standby, invaluable for adding to hot drinks if you cannot re-educate your palate to do without a tinge of sweetness. Liquid sweeteners, which contain 98 per cent fewer kilojoules than sugar, are useful for cooking. Add them to foods away from the cooker, when they are cooling or cold, to stop any bitter taste. Powder and granulated sweeteners aim to look as much as possible like sugar; some are actual sugar granules coated with saccharin to give extra sweetness: others are concentrated saccharin powders which must be used sparingly. Newer lowkilojoule, granulated, sugar-free sweeteners have 90 per cent fewer kilojoules than sugar, but can be used spoon-for-spoon like sugar, which makes them easier to cope with.

Diet drinks Canned fizzy drinks have almost no calories and are good thirst-quenchers. Low-kilojoule mixers allow slimmers to have the occasional alcoholic drink and half the normal calories. Low-kilojoule squashes are also very useful.

Low-kilojoule dressings These are a useful aid to more interesting diets which makes you to slim fast. Low-kilojoule tomato sauce is another saving.

Low-kilojoule spreads A good replacement for butter, giving you more spread on your bread in a kilojoule-controlled diet. Some taste better than others, so shop around. Processed cheese spreads also give a kilojoule saving.

Bread Slimmers' breads are lighter, weight for weight, than normal bread, but are usually no different in terms of nutrients. Because they weigh less, their energy value is about half that of ordinary bread. They are worth considering, but not if you eat twice as many slices in an attempt to fill yourself up.

Crispbread Made from wholewheat grains of rye or wheat, usually baked with just a little salt, vegetable oil or water, these are good slimming standbys. As crispbread normally retains the husks of grain, they provide fibre and roughage.

Preserves Low-kilojoule jams usually have to be kept in the fridge and have about half the kilojoules of ordinary jam.

Canned fruit Unsweetened, natural juice or water instead of syrup means a kilojoule-saving. A useful substitute, when fresh fruit is not plentiful or available.

Milk Skimmed milk and milk with the cream removed are both great slimming aids.

Soups Tins of kilojoule-conscious soup may prove time-saving, but you can easily make your own diet soups for even fewer kilojoules per serving.

Vegetable cooking spray This provides a less greasy way to pan fry, bake or grill. Since frying is normally forbidden on any slimming diet, this could open up new cooking choices. Spray it onto a cold pan and let the pan warm before adding food,- don't be tempted to spray more than the recommended amount.