Lisa Markwell: Food labels made simple: if you can't say it, don't eat it

In the same way that the only honest weight-loss advice should be eat less, move more, the only honest way to label food would be good for you, OK and bad for you. Instead, as we know from yesterday's announcement of a voluntary labelling system to be introduced into supermarkets next year, we will have high, medium and low. This replaces the nebulous "traffic lights" of red, amber and green that many retailers have been using.

Any system that makes harried and hungry consumers think about what they toss in their basket is a good thing. But really, can't we do better than a combination of colour coding, wording and percentages that does little to simplify and not much to cut obesity?

I can see the thinking: consumers with the least time and – perhaps – nutritional nous need guidance. A combination of differing package sizes, weights (some are grams and some millilitres for almost identical products) and portion-size suggestions is enough to confuse Heston Blumenthal and his digital scales.

But let's get real – it's what we're eating that's more of a problem, not how much of it. By the inexact method that has been devised (and will be debated by the Department of Health and interested parties today), a calcium-packed cheddar would have warning signs on it, being high in fat, and salty. Isn't a little bit of cheese better for us than a processed cheese-flavoured product? You know the ones, the TV-advertised ones that come in bright, cartoon-clad packaging; the ones your children clamour for.

My young daughter once trailed around Sainsburys begging for one of these and, bossy-boots that I am, I said that if she could read me the ingredients, she could have it (knowing full well that chemical names with eight syllables are beyond the comprehension of, well, all of us).

What should be printed large on the front of all processed food packaging – because that's what we're really talking about in terms of what impacts on health – is a list of what's inside. Many claim they are preservative- and colour-free, but there are plenty of other unpronouncable components. Printing them in microscopic lettering inside a fold on the bottom of a box should be banned. Disguise less, inform more.

An aside: Asda's corporate affairs director Sian Jarvis claimed on Radio 4's Today that the confectionery (largely chemically sweetened, colour and flavour enhanced, chewy pap) it sells at two out of three of every checkout in its stores makes no difference to "busy mums' buying habits". So, how about putting apples or seed bars there instead. No? Thought not.