For the past three years a row has waged within the food industry about the best – and most honest – way to label food so that consumers know how much fat, saturated fat, sugar and salt is in each product.

Tesco and most leading food companies have opted for GDAs – guideline daily amounts, which give shoppers an idea of how much of a their daily allowance for salt and sugar is contained in each product. Campaigners argue that these labels rely on shoppers understanding percentages – which most do not.

Sainsbury's and some other food companies prefer "traffic lights" labels, which colour code products. Too much salt, for instance, merits a red light, an acceptable amount of sugar merits a green light.

Some food companies say this is far too simplistic and means certain classes of food will be shunned by consumers, with fruit juices, for instance, automatically being labelled with a red sticker because of their sugar content.

The Food Standards Agency is halfway through a comprehensive investigation into the best method, and an interim study has found that most consumers are still very confused by both methods.

Some shoppers feel "cheated", the study said, by the labels only referring to a "portion" not the whole pack. Many failed to understand that red meant bad, and green meant good, according to the independent study, headed by Sue Duncan, a former chief social researcher for the Government.

It suggested that the words High, Medium and Low were used alongside any colours to "assist comprehension".

A spokesman for the FSA said: "From the research so far it's clear that consumers welcome, and want, front-of-pack labelling and are frequently using them to inform their choices. However, some people are clearly confused and we need to quantify that."

The FSA will make a recommendation next year as to which method the UK food industry should adopt.

"We've been clear from the start that a single method that all shoppers understand is the way forward. Everyone needs to understand it and get used to it," he added.

Source: Telegraph