The rest of this briefing focuses on how health targets for retailers could be designed, implemented and enforced to reduce obesity. 

Large retailers make up over 95% of the grocery market and are the gatekeepers of the majority of what we eat.

As the major link between food producers and consumers, they hold considerable power and influence over the whole food system. They should be held accountable for the role they play in determining the health of the nation.

However, a mandatory targets policy must not be unduly burdensome for industry, nor detrimental to its bottom line.

For this reason, the key requirement of our work was that targets must lead to a reduction in total calories purchased, while not leading to a reduction in the total value of products sold.

Our research looked at a range of options for retailer targets, with a focus on assessing the best measures for improving health and reducing obesity. To do this, we have analysed food purchasing data from Kantar’s Worldpanel Division [6], an international market research company. The dataset comprises food and drink purchases taken into the home in 2021 for a sample of approximately 30,000 British households, which we used to model the potential impact of targets on calorie purchasing and population obesity rates (see Box 1 or technical appendix for further detail of the analysis and modelling). Alongside this, we engaged with experts from the UK food industry (including some of the biggest retailers), policymakers, health charities and academia through interviews and a workshop to assess the feasibility of different target options. We also commissioned an economist to appraise the policy (see economic assessment), and sought legal advice from the legal firm Kingsley Napley LLP, which was incorporated within this note and the implementation plan.

Box 1: summary of analysis and modelling approach
Box 1: summary of analysis and modelling approach (for more information, see technical appendix)
  1. We used 2021 food purchasing data from a representative sample of 30,000 British households to conduct our analyses. We used nutritional information and sales data to calculate retailer (branded and own brand) sales weighted averages for each health metric. 
  2. We weighted sales of food by the volume (in kilograms) of products sold. This approach is consistent with that used by the Office for Health Improvement and Disparities (OHID) in the calorie reduction programme and gives more influence to products with higher sales, while capturing changes in portion sizes and multipacks.
  3. According to these assigned metrics we split the dataset into ‘healthy’ and ‘unhealthy’ products, with the definition of ‘healthy’ being dependent on the metric being used. 
  4. We then applied a range of percentage decreases in sales and nutrient composition shifts (reformulation) across unhealthy foods, alongside increases in sales of healthy foods, to model various scenarios by which businesses could achieve a given target.
  5. Based on the outputs of these models, we chose a set of targets for retailers to meet that we considered both ambitious and achievable. We only chose scenarios where the total value of food sold did not decrease, and a significant reduction in calories was estimated.
  6. Lastly, we modelled the estimated impact of these calorie reductions on the population excess weight distribution.

[6] All analysis and interpretation was conducted independently of Kantar Worldpanel. Kantar has not independently verified the findings.

Authors

Lydia Leon

Lydia Leon

Lydia Leon

Senior Analyst, healthy life mission

Lydia works as a senior analyst in the healthy life mission team.

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Husain Taibjee

Husain Taibjee

Husain Taibjee

Analyst, healthy life mission

Husain joined Nesta in 2022 as an analyst and will help to deliver Nesta’s healthy life mission.

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Lauren Bowes Byatt

Lauren Bowes Byatt

Lauren Bowes Byatt

Deputy Director, healthy life mission

Lauren is the Deputy Director of the healthy life mission.

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Hugo Harper

Hugo Harper

Hugo Harper

Mission Director, healthy life mission

Hugo leads Nesta's healthy life mission.

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Elena Mariani

Elena Mariani

Elena Mariani

Principal Data Scientist, healthy life mission

Elena is a principal data scientist for the healthy life mission.

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Isabel Stewart

Isabel Stewart

Isabel Stewart

Data Scientist, Data Analytics Practice

Izzy is a Data Scientist working in the Data Analytics practice.

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Jessica Jenkins

Jessica Jenkins

Jessica Jenkins

Senior Policy Advisor (Health), Rapid Insights Team

Jess is a senior policy advisor in our Rapid Insights Team (RIT).

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Caitlin Turner

Caitlin Turner

Caitlin Turner

Senior Analyst, healthy life mission

Caitlin joins Nesta as a senior analyst in the healthy life mission.

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