What types of nutrition menu labelling lead consumers to select less energy-dense fast food? An experimental study

• Kilojoules, with or without traffic lights, associated with lower energy selections.
• Menu labelling is an equitable means of encouraging healthier fast food choices.
• Traffic light labels used most in making selections, percent daily intake least.
• Menu disclosure of energy-content has potential to yield population health benefits.

This study assessed whether the inclusion of kilojoule labelling alone or accompanied by further nutrition information on menus led adults to select less energy-dense fast food meals. A between-subjects experimental design was used with online menu boards systematically varied to test the following labelling conditions: none (control); kilojoule; kilojoule + percent daily intake; kilojoule + traffic light; and kilojoule + traffic light + percent daily intake. Respondents were 1294 adults aged 18–49 in Victoria, Australia who had purchased fast food in the last month and were randomly assigned to conditions. Respondents in the no labelling condition selected meals with the highest mean energy content and those viewing the kilojoule and kilojoule + traffic light information selected meals with a significantly lower mean energy content, that constituted a reduction of around 500 kJ (120 kcal). Respondents most commonly reported using the traffic light labels in making their selections. These findings provide support for the policy of disclosure of energy content on menus at restaurant chains. Given the magnitude of the reduction in energy density reported, and the prevalence of fast food consumption, this policy initiative has the potential to yield health benefits at the population level.