Making healthy choices: traffic lights, percentages or just a nice looking packet?

29th November 2007

There has been much debate over how we should rate the healthiness of our food: traffic lights or percentages? Market research generally says people prefer the Food Standards Agency’s traffic lights system, while industry giants argue that traffic lights are too simplistic and offer a more detailed system showing percentages of Guideline Daily Amounts (GDA). User Vision put a few of these systems against each other in a simple usability test and found that attractive packaging and healthy claims often make up our minds before we even look at any labelling system.

As part of World Usability Day, User Vision conducted an informal usability study of which food labelling system is the most helpful when deciding what is healthy and what is not. Participants were observed as they chose which lunch they thought was the healthiest, and also as they made individual comparisons of similar products. Each lunch was made up of comparable products from different supermarkets: a packet of crisps, an egg sandwich, a juice, and a small cake, to make the choices quite difficult.

Whether the traffic lights and the GDA were most effective was not easy to tell, as they were often not used at all in the decisions made by participants. Sometimes participants would compare the numbers found on each packet, and still be at a loss as to which was healthiest – the crisps with more salt but less fat, or more sugar and less calories?

A more decisive influence on participants seemed to be attractive packaging, high quality photography, health claims made on the packet, and the perception of brand. The test conditions were far from being realistic to supermarket conditions, but it is likely that given a shorter time to choose, and no facilitator checking the choices made, people would be even less likely to go to the trouble of comparing percentages and colours in the short minutes of a lunch break or the quick weekly shop. The preliminary results found in this usability test would make a more in-depth test very interesting, and potentially much more useful than the reams of opinion-based market research on the debate to date.

Interestingly enough, it seems that the GDA system was most effective when participants did take the time to make a direct comparison of nearly identical products – two packets of crisps for example. This could be because the various numbers are clearly presented for comparison in the GDA method and easily compared, whereas the traffic light system aims to simplify things with three colours. As most packets of crisps will show roughly the same array of traffic light colours – usually reds and ambers – this system may not be as useful for such a close comparison of the same type of food as the GDA.

Conversely, traffic lights excel at giving at-a-glance information, banking on the fact that most people don’t pick up two packets of crisps to read the labels, or compare the fat content to the nearest tenth of a gram.

Unfortunately, such a visual medium has to compete with the plethora of other visual and aesthetic elements of packaging: the colour and quality of the packet, photography, and other graphic design can make a product look organic and healthy or cheap and artificial in an instant; before the FSA or GDA labelling is even noticed. Claims on the packet such as ‘free from preservatives’ seem to also be quite effective in influencing our purchases, and might just stop us from getting out our calculators in the supermarket.

Why is there so much debate over how to present these GDA numbers when most of us seem to ignore them in favour of a nice looking packet? Perhaps ‘organic, freshly pressed apple juice’ and ‘one of your five a day’ appeals to most of us as ‘healthy’ more than 1% 0% 0% 18%, or green, green, green, red.

Following the training from User Vision I feel much more confident and aware of users and their requirements online. Really interesting course.

Online Customer Experience Manager, Clydesdale Bank.