Impact of food environment policies and food insecurity on less healthy food consumption, obesity and health economic outcomes – a model-based appraisal

Background:

Obesity and food insecurity are rising in the UK, and policy makers need to identify evidence-based strategies to reduce these. Both are strongly related to environmental factors influencing food access and availability. Policies that alter the food environment may reduce obesity, but they may have unintended consequences including differential effects on food secure versus insecure populations.

Agent-based models (ABMs) are a promising tool for evaluating public health policies, considering the complexity of behaviour and individual-environment interactions. However, their application to dietary policy has been limited.

Aim: To assess the health, economic and inequality impact of food environment policies across localities using a categories of food insecurity lens. Research questions:

RQ1: What conceptual model describes how food insecurity, alongside other factors within the food system, influences the impact of food environment policies on high fat, salt and sugar (HFSS) food consumption and obesity?

RQ2. How can a combination of datasets inform the estimation of structural equation models and a synthetic population to examine how differential exposure to environment factors including deprivation affect household food insecurity and hence influence different food choices for individuals, households and communities?

RQ3: What is the structure and parameter estimation for an agent-based model that incorporates how environment and food insecurity factors influence individuals’ food choices so that the model is calibrated to the emergent, contrasting trends between 2018 and 2023 in HFSS consumption by food insecurity categories and obesity rates for population subgroups across local authorities in Greater Manchester?

RQ4: What are the impacts of three food environment policies (advertising, outlet restrictions, accessibility of healthy food) on health outcomes, labour market outcomes and inequalities for population subgroups across Greater Manchester localities including those defined by food insecurity category?

Methods:

The study takes a multidisciplinary approach involving stakeholder engagement, conceptual modelling, data synthesis, structural equation modelling, and empirical ABM development including comprehensive model calibration and validation. We will integrate data from surveys and environmental databases to create a synthetic population. The ABM will be calibrated and validated using trends in obesity and HFSS consumption for 10 local authorities across Greater Manchester.

We will use the ABM to simulate three dietary policies and quantify the impact on HFSS consumption, obesity, and health and economic costs and benefits. Timelines for delivery.

The project has four work packages across a 36-month period. We will specify model structure and perform data integration in the first year of the project. The second year of the project will build and validate the ABM. The final year of the project will perform health economic analysis for three food environment policies.

Anticipated impact and dissemination.

We will publish 7 open-access publications across health, nutrition and modelling journals. We will present at key obesity and public health conferences. Our work will build a robust framework for UK-focused ABMs of food policies with a food insecurity lens. We will develop policy briefing documents with stakeholders and public representatives to communicate key findings.