A realist evaluation of a public health community of practice advocacy project to restrict outdoor advertising of high fat, salt, and sugar foods

Evaluation Completed May 2022

What does the research mean for Local Authorities?

This Project seeks to provide a regional approach to the development of local policies to support the reduction of exposure through advertising to foods high in fat, salt and sugar (HFSS foods). This policy change process is complex and the advocacy role challenging, but it is an area many Local Authorities (LAs) are beginning to pursue. This evaluation will help the local region and other LAs to better understand: what works in influencing policy change in this area; who the important stakeholders are and how to engage them; and the skills, competencies and resources that a policy advocate requires to undertake this work 

What does the evaluation research mean for the Public?

The findings from this study will support LAs in their work to create healthier local environments which can be important in determining the public’s health. Obesity remains a government priority with 63% of adults above a healthy weight and 1 in 3 children leaving primary school overweight. Obesity is a risk factor for a range of chronic diseases and those living with obesity are more likely to be seriously ill if they contract COVID-19. Exposure to advertising of HFSS products influences children’s food choices in the short and long term and a reduction in advertising may influence adultspurchases and consumption 

How are the public involved in the evaluation?

Our Public and Patient Involvement (PPI) Co-Investigator was involved in our co-production workshops to develop the theory of change and help design our evaluation. Following this, a locally recruited Lay Advisory Panel of 5 members was been put in place. The panel have met at regular intervals to discuss research design, perceived challenges to implementing HFSS food advertising policy change and impact on the local citizens. They have also fed into data collection tool design fed back on interim findings and helped put in place a dissemination plan.   

Lay summary of research

Image courtesy of Sustain

What is this evaluation about?

The aim of this evaluation is to find out what makes it easier or more difficult for local authority public health professionals and others to influence council policy on the advertising of HFSS products.

What do we already know?

Reducing levels of obesity is a key Government priority and the advertising of HFSS products influences children's food choices and may influence what adults buy and eat. Restriction of advertising is one approach to making a more supportive environment that helps reduce obesity.

What don’t we know?

We do not know what helps to influence public policy development and change around obesity and healthy weight. We do not know what exactly helps or hinders public health pracitioners and others to influence council policy. We do not know which actions or methods may contribute to changes in council policy.

Why is an evaluation necessary?

Council policy changes can help to improve the public’s health. In this case, the restriction of advertising of unhealthy foods may lead to people changing what they eat in the long term. Getting agreement to limit advertising is a complicated policy change which many local authorities in the UK are interested in. Our evaluation will help others know how to make similar complicated policy changes successfully. Getting a policy change needs people to promote an idea and work together to put it into practice. Understanding how this is best achieved will help to identify the skills and attributes needed to make successful policy changes which may help improve the public’s health.

How will it be carried out?

The project to restrict advertising of unhealthy foods is running for a year, our evaluation will run alongside the project. A survey will identify if there is advertising of unhealthy foods in council owned spaces and if there are any restrictions. During the project, the people who are trying to make the policy change will be interviewed three times. They will be asked about how easy or difficult it is to get the policy changed. We will also interview other people, known as stakeholders, who are interested in this issue or could affect if it is successful.

What will we do with the results?

The findings will describe and explain how successful this policy change is. It will explain what makes it easier or more difficult for local authority public health professionals and others to influence council policy. It will also describe what individuals need to do to make their change successful. We will use a range of medium to share our results locally and nationally including: local evidence briefings, academic publications and presentations.

Local Authority/Partner(s)



PHIRST South Bank Research Team

Dr Susie Sykes (PI), Dr Megan Watkins, Dr Cath Jenkins,  Dr Matthew Bond, Prof Jane Wills 

Contact: phirst@lsbu.ac.uk