'Traffic light' system produces long-lasting results

A ‘traffic light’ labelling system used in a US hospital cafeteria has resulted in positive changes up to two years after it was first implemented.

After initially reporting good results several months after the program was launched, a team from the Massachusetts General Hospital (MGH) reported in the American Journal of Preventive Medicine that the changes have continued up to two years after the labelling intervention was introduced.

“Our current results show that the significant changes in the purchase patterns of both hospital employees and all customers resulting from the labels and the choice architecture program did not fade away as cafeteria patrons became used to them,” said Anne Thorndike, MD, MPH, who led the study. “This is good evidence that these changes in healthy choices persist over time.”

The program was initiated in March 2010, with the first phase involving the application of ‘traffic light’ labels - green for healthy items such as fruit, vegetables and lean protein; yellow for less healthy items; and red for those with little or no nutritional value. Several weeks before the labels were introduced, the cafeteria’s cash registers began to track purchases of items according to their label.

The second phase, launched three months after the labels were introduced, saw cold beverages, pre-made sandwiches and chips rearranged to display healthier items at eye level, while less healthy options were placed at lower levels.

The team reported in March 2012 in the American Journal of Public Health that, at the end of the initial six-month study, significant increases in the purchase of ‘green’ labelled items and reduced purchases of ‘red’ labelled items had been recorded. The largest changes were noted in terms of beverage purchases.

A subsequent study in the September 2012 American Journal of Preventive Medicine revealed that employees enrolled in a program in which their meals could be paid by payroll deduction showed similar changes towards ‘green’ products across all racial and ethnic groups, as well as job types.

Analysing the 24 months following implementation of the program, the study showed that the changes present at the end of the first year were virtually unchanged at the end of the second.

It also showed that:

• purchases of ‘green’ items had increased by 12%
• purchases of ‘red’ items had decreased by 20%
• purchases of ‘red’ beverages dropped by 39%
• purchases of ‘green’ beverages increased by 10%

“These findings are the most important of our research thus far because they show a food labelling and product placement intervention can promote healthy choices that persist over the long term, with no evidence of ‘label fatigue’,” said Thorndike.

“The next steps will be to develop even more effective ways to promote healthy choices through the food service environment and translate these strategies to other worksite, institutional or retail settings.”