Guideline Daily Amounts are marginally ahead of traffic lights in terms of usefulness, The Grocer can reveal.

In a boost for the growing band of big name companies adopting GDAs instead of the FSA's recommended traffic lights, exclusive research for The Grocer by Harris Interactive involving more than 2,000 people indicated that 33% thought GDAs were more useful.

A quarter of shoppers found traffic lights more useful, while 42% rated both schemes equally.

When asked just whether they found the GDA scheme useful, 66% of respondents said yes. Shoppers at Tesco, which originally developed the scheme, were more likely to find the scheme useful than other shoppers.

Some 63% of those surveyed found traffic lights useful. However, in a blow to Sainsbury's, which has developed the scheme using its Wheel of Health traffic light system, slightly fewer of its shoppers than the total sample found the system useful, with only 60% saying yes.

A Sainsbury's spokeswoman said: "The great news is that six out of ten people are using traffic lights to help them choose a better diet. A difference of 3% is not significant.

"Moreover, recent research from YouGov found that 93% of people want the food industry to unite and adopt one clear food labelling system; the favoured one was traffic lights.

"In this research, three in four people, 75%, understood this labelling whereas 64% had no idea what GDAs are."

The Harris research for The Grocer also indicated that 73% of respondents sometimes or always looked at food labelling before buying a product. Women were far more likely to look at food labelling than men, with 34% of men surveyed saying they hardly ever or never checked the nutritional content of products. Shoppers were most likely to look for fat content, followed by sugar, salt and artificial additives.

Shoppers thought they were more health conscious than a year ago. Only 3% felt they were less health conscious, which suggested continual news coverage about health had led to an impact on people's intentions to live more healthily."

Consumers were no longer throwing items into their trolleys, according to the Harris research. People were diligently reading the all-important labelling and making informed choices.Harris research reveals..

73% of shoppers sometimes or always look at labelling before buying

33% of shoppers find GDAs more useful than traffic lights

25% of shoppers find traffic lights more useful than GDAs

42% of shoppers find traffic lights and GDAs equally useful

63% of shoppers find traffic lights useful

66% of shoppers find GDAs useful

60% of Sainsbury's shoppers find traffic lights useful

69% of Tesco shoppers find GDAs useful