Frozen ready meal intervention trial

The effect of a relative availability intervention on the sale of vegetarian meals from COOK

The Problem

Poor diets are a leading cause of ill health. Reducing meat consumption could reduce the environmental impact of the food system. Changing the food environment can influence dietary choices. Previous research suggests that increasing the availability of vegetarian meals is associated with increased sales in canteen settings, but less is known about retail settings.

Research question

What is the impact of increasing the relative availability of vegetarian ready-meals on display on the proportion of vegetarian ready-meal sales?
What is the impact of increasing the relative availability of vegetarian ready-meals on display on the total ready-meal sales?

The Intervention

Increasing the relative availability of vegetarian products through increasing the freezer facings for vegetarian ready meals. Facings refers to the amount of shelf space given to a product. Currently, vegetarian ready meals comprise approximately 29-33% of freezer facings. The intervention will increase this to approximately 42-45%.

Target Population

Selected COOK stores where the intervention will be randomised for a specified time.

Key Outcomes

Sales of all ready meals will be obtained from electronic point-of-sale tills before, during, and after the intervention period. We will collect details of the vegetarian product names, the units sold, their sales revenue (£), the ingredient list and the nutritional composition of the products stocked and sold during the intervention weeks.

Preliminary or pilot studies

This study does not include a preliminary or pilot study.

Evaluation design

A stepped-wedge randomised controlled trial to measure the effect of the intervention on meal sales.
A process evaluation to understand how the intervention was implemented and its acceptability in a real-world setting.
An economic evaluation of the intervention to determine intervention costs and projected impact on population health and the environment.

Sample size

Five stores will be randomised to receive the intervention over a six week period.

Data collection

Sales data will be obtained from electronic point-of-sale tills. The corresponding product data (product name, size, nutritional composition, etc.) will be collected from the retailer.

Process evaluation

The process evaluation will assess the quality of implementation of the intervention and the barriers to and facilitators of implementation. The process evaluation will involve semi-structured interviews with store managers and customer-facing staff and interviews with key decision-makers.

Economic evaluation

The trial team will assess the incremental cost of implementing the intervention, which measures the difference in cost between the intervention and control periods. This includes additional costs such as increasing the availability of vegetarian ready-meals, potential additional staff costs, and any revenue losses resulting from implementing the intervention. These costs will then be offset against any change in outcomes to form an economic evaluation.

Modelling

Utilising the PRIMEtime model, the impact of increasing the relative availability of vegetarian meals on diet-related disease morbidity and mortality rates will be modelled.

Governance

The University of Oxford is currently developing a data-sharing agreement between the University and the retailer. Ethical approval will be sought from the Central University Research Ethics Committee at the University of Oxford. The research team consist of SALIENT researchers from Oxford, Birmingham and LSHTM.

Proposed outputs

We will publish paper(s) in peer-reviewed academic journals. We will also present the trial findings at conferences and through direct communication with policymakers and the retail partner.