Q. Are foods labelled light any good if you're on a diet? Or are they full of sugar to make up for the drop in fat?
A. Foods labelled ‘lite' or ‘light' can help you cut fat and kilojoules (calories) - but not in every case. ‘Light' does not always mean low-fat. Light can refer to texture, flavour, colour or salt content as well as less fat and kilojoules. For example, light olive oils have a milder, more bland flavour but carry exactly the same level of fat as ordinary oils. Light potato crisps have less salt or are thinly-sliced, but not significantly lower in fat.
Light sour cream or light cream cheese has about half the fat AND half the kilojoules of regular products (18% compared to 35%). Using them instead of the full-fat version saves you fat and kilojoules. But use them in your usual quantities - you can't eat TWICE as much just because they're lighter.
In contrast, light muesli bars, muffins and biscuits often don't save you much at all. If you want them to have a soft texture and attractive taste, something has to take the place of fat in baking. It's usually extra sugar or flour or some thickener/aerater/binder. So the fat may drop but not the final kilojoules.
Before you buy light products, do the sums! Put the regular and the light versions side by side. Compare the nutrition information panels to work out just how much fat AND KILOJOULES you get in a serve.