According to the study, published in the journal Preventive Medicine, a simple colour coded labelling system encouraged customers in a hospital cafeteria in Massachusetts to purchase the most healthy food items.
A European dispute
Such “traffic light” systems are intended to simplify the nutritional value information displayed on the pack, but have been met with some strong criticism from the food industry.
In June this year the UK introduced a voluntary front-of-pack nutrition labelling system whereby guidance daily amounts (GDAs) are illustrated using the three traffic light colours.
All major retailers and a handful of major manufacturers signed up to scheme, but the move faced reproach from some such as the trade body FoodDrinkEurope which said the classification “could fragment the EU internal market” where monochrome GDAs are already in place, while others said such grading is too simplistic.
Red, yellow, green
The researchers looked at the purchase choices made before and after the implementation of the red, yellow, green label system in 2010, maintaining that the demographic of the cafeteria customers did not differ greatly across this time frame.
The 2013 survey largely involved hospital employees (81%), and overall 59% were female and 58% aged 40 or over. Survey respondents self-reported their race, and 77% were white, 11% black, 6% Hispanic/Latino and 6% were Asian.
This latest study, which adds to an emerging scientific discourse on the topic, categorised the food products available into four groups - food entrée, food item, food condiment, or beverage - and rated products on three positive and two negative criteria.
The positive 'healthiness' was defined by whether the main ingredient (one of the first three ingredients by weight) was a fruit or vegetable, whole grain or lean protein/low fat dairy. The two negative criteria were saturated fat and calorie content.
Spot the difference
“At baseline, 46% of respondents identified health and nutrition as being an important factor in making their food or beverage choice; after the labelling, this proportion increased to 61%,” wrote the researchers.
“The importance of taste and price also increased significantly during the labelling intervention compared to baseline, and the importance of convenience decreased,” they added.
However the survey found that there was no significant difference between the baseline and the intervention periods in the proportion of respondents who reported that they “usually” or “always” choose a food that is healthy.
A higher proportion of respondents reported that they looked at nutrition information once the traffic light system was in place, with this percentage increasing from 15% to 33%.
These changes led the researchers to claim that: “Traffic light food labels prompted individuals to consider their health and to make healthier choices at point-of-purchase.”
Source: Preventive Medicine
2013; 57 (4): 253 DOI:10.1016/j.ypmed.2013.07.001
“A traffic light food labeling intervention increases consumer awareness of health and healthy choices at the point-of-purchase”
Authors: L. Sonnenberg, E. Gelsomin, D.E. Levy, J. Riis, S. Barraclough and A.N. Thorndike