GDA supporters say they will resist any government attempt to impose traffic lights ahead of new EU laws on nutrition labelling.

Government pressure on retailers and manufacturers to adopt traffic lights is likely to be ramped up this week, after the Food Standards Agency published its research into nutrition labelling, which claimed consumers best understood a combination of text, traffic lights and GDA information.

The project management panel that carried out the research concluded that "the coexistence of a range of front-of-pack labels in the marketplace causes difficulties for shoppers".

Key findings of fsa study:
A label combining text and traffic lights achieved the highest levels of consumer comprehension (71%)

The label combining text, traffic lights and GDAs, as used by McCain Foods, achieved 70% comprehension, but was favoured by the panel because the inclusion of % GDA helps shoppers determine the level of individual nutrients

The wheel format, as pioneered by Sainsbury's, was one of the weakest performers in the comprehension test

Some shoppers do use energy (calories) to decide how healthy a product is, but the inclusion of energy has no effect on comprehension
But companies currently using GDAs maintained changing to traffic lights before Europe voted on the Consumer Information Act, which will create a single mandatory labelling scheme, was not realistic.

"There is no way anyone is going to change now, knowing the EU is working on this proposal," one regulatory affairs manager for a major multinational said.

The view was echoed by the British Retail Consortium. "Until a final decision about a front-of-pack labelling scheme is taken at European level, it would be premature for the UK to adopt any new regime of its own," said director general Stephen Robertson. "Changing and then changing again would just produce extra costs and customer confusion."

The FSA will consider its advice to ministers at a board meeting next week, but NGOs have been quick to demand action.

"Any company that doesn't now adopt the public's favourite system will be exposed as putting their profits before their customers' health," said Christine Haigh, Children's Food Campaign coordinator.

The current mishmash of food labelling systems had confused the public for too long, according to the British Heart Foundation. "It's time for food companies to support one system and ensure shoppers get the at-a-glance information they need," said chief executive Peter Hollins.

The FSA study investigated which of 10 labelling schemes best helped consumers understand key nutrition information so they could make informed choices. The two preferred labels were: one combining the words 'high', 'medium' and 'low', traffic-light colours and % GDA; and one combining only words and traffic-light colours.

The research has come in for criticism, however, for being too simplistic and failing to look at consumer attitudes towards labels.

"I thought they looked at the simplest questions they could have looked at," said one source. "They said they were looking to see if consumers could choose the healthiest option, but didn't give a definition of healthiest. They could have put in additional questions and received far more in-depth information."