The aim is to undertake a cluster randomised controlled trial to assess the effectiveness of PACE food labelling in reducing young people's purchasing of discretionary foods in secondary school canteens. Physical activity calorie equivalent (PACE) food labelling aims to show the number of minutes or miles/kilometres of physical activity equivalent to the calories contained in food/drinks.

Physical activity calorie equivalent (PACE) food labelling aims to show the number of minutes or miles/kilometres of physical activity equivalent to the calories contained in food/drinks. Evidence suggests that PACE food labelling may influence food/drink choice. Most research in this area however have tested PACE food labels with adults and/or have tested hypothetical food choice scenarios. Studies in real world contexts with young people are needed to see if PACE food labels could help them make healthier food choices.

The aim is to assess the effectiveness of PACE food labelling in reducing young people's purchasing of discretionary foods in secondary school canteens. A cluster randomised controlled trial with a nested qualitative study will be conducted. Secondary schools will be randomised to either display PACE labelling near discretionary foods or continue with their usual practice. The intervention period will be up to 6 weeks. Anonymised purchase data will be collected throughout the study period.

Qualitative interviews will be conducted with students in the intervention schools to explore their views of the PACE labels such as perceived influence of the PACE labelling on their food selection.

Secondary schools:

Inclusion Criteria:

• Secondary schools that admit young people aged between 10 to 19 years.
• Sell at least one type of cake and/or at least one type of sweet biscuit for at least 2 days per week up to a 6 week period (or equivalent), and have sold the same cake(s)/biscuit(s) before the study (for a minimum of 4 weeks).
• Able to provide to the researcher with anonymised purchase data for study periods. Data to include number of units sold and dates sold of the chosen food item(s).
• A PACE label could feasibly be placed near to the study elected food item(s) in a school canteen used by students.
• Not participating in any other school trials or initiatives.

Exclusion Criteria:

• Secondary schools not meeting the inclusion criteria.
• Secondary schools that admit young people below the age of 10 years or above the age of 19 years.