Light is the most quietly technical word in a supermarket. It reads like a mood — airy, forgiving, lower stakes — and it is in fact a piece of arithmetic with a legal definition and one significant gap in it.
The definition
Under Regulation (EC) No 1924/2006, light and lite must meet the same conditions as reduced: the content of the named nutrient must be at least 30% lower than in a comparable product. The claim must also say which characteristic makes it light, which is why packs read “light — 30% less fat” rather than just “light”.
Two exceptions are written into the same clause:
- For micronutrients, a 10% difference is enough.
- For sodium, a 25% difference is enough.
Where the gap is
The regulation fixes the percentage. It does not fix the reference product beyond “a similar product”. So the comparison is internal to a category, and the category can be generous.
A light mayonnaise with 30% less fat than standard mayonnaise is still a high-fat food, because standard mayonnaise is mostly oil. Light crisps are still crisps. A light beer has less alcohol, or fewer calories, or both, depending on the market — and in some countries “light” on a beer is about alcohol while on the next shelf it is about energy.
Thirty per cent less of a lot is still a lot. The claim is a relative statement wearing the clothes of an absolute one.
Reduced sugar, and where the energy goes
Reduced sugar is the one worth checking hardest, because sugar does two jobs in a food — sweetness and bulk — and removing it means replacing both. Sweetness usually comes back as a sweetener. Bulk comes back as starch, polyols, fibre or fat. The result is a product with genuinely less sugar and often almost identical energy.
That is not deception. The claim was about sugar and the sugar really did fall. It is simply a different claim from the one a shopper is usually making in their head, which is about calories.
The check takes seconds: compare the energy per 100 g of the light version and the standard one, side by side on the same shelf. If the two are within a few per cent of each other, the light version is doing something for you other than what you assumed.
When light is worth buying anyway
Often. Reduced-salt versions of things you eat daily — bread, stock, canned pulses — are a straightforwardly good swap, and 25% is the legal minimum rather than the typical achievement. Lower-fat dairy is a real reduction in saturated fat with nothing sneaking back in. Light versions of foods where the removed nutrient was the main energy source behave exactly as advertised.
The rule of thumb is not “distrust light”. It is: read the word after it, then check the number it refers to against the standard product. The regulation has already guaranteed that the difference is at least 30%. It has guaranteed nothing about whether 30% was enough to matter.
