Title: Population interventions to improve diet in England: An evidence synthesis of the effectiveness of mandatory, voluntary and partnership approaches
Funder: Department of Health and Social Care

Abstract: BACKGROUND: Poor diet is thought to cause more deaths than any other factor in England. In response, the Government has introduced a range of interventions to improve diet for the whole population. Population interventions may be mandatory, such as the Soft Drink Industry Levy, where producers who do not reduce a certain amount of sugar in their drinks are taxed. Interventions can also be voluntary, such as childcare settings like nurseries having the choice to use a guideline on food and drink for babies and toddlers (as opposed to state schools which must follow food standards). And interventions can be arranged as partnerships between the public and private sectors._x000D_ _x000D_ AIM and OBJECTIVES: This research aims to inform more effective responses to poor diet in England by appraising which population interventions are most effective to improve diet, and understanding what factors influence their effectiveness._x000D_ _x000D_ METHODS: The study will comprise a systematic review of the literature covering how policy interventions to improve diet should work in theory, how they have worked in practice and whether they have been effective. A systematic review of the literature involves developing and following a detailed strategy to identify, appraise and bring together all relevant studies on a particular topic. The findings of the literature review will then be presented to a group of key stakeholders, specifically practitioners and policy experts with experience designing, implementing, monitoring and/or evaluating relevant population interventions. These stakeholders will work together with the research team to discuss how improvements to population interventions for diet in England can be made, in light of the findings of the literature review._x000D_ _x000D_ BENEFITS: Knowing which population interventions on diet work and how to improve them will help reduce the overall disease burden in the UK, diet-related inequalities and NHS costs. Moreover this study helps to identify problems with how interventions are currently evaluated, and proposes recommendations for more effectively monitoring and reporting future interventions.

Lay abstract: AIM_x000D_ To search systematically for, appraise the quality of, and synthesise evidence on the effectiveness of population interventions to improve diet, including mandatory interventions, voluntary mechanisms and public-private partnerships, and to share the evidence synthesis with stakeholders with a view to informing more effective responses to poor diet in England._x000D_ _x000D_ BACKGROUND_x000D_ Poor diet is estimated to be the largest contributor to overall disease in England. In response to this problem, the Government draws on a range of population interventions to improve diet. This research is interested in what types of population interventions, whether they be mandatory interventions, voluntary mechanisms or public-private partnerships, most effectively improve diet. Mandatory interventions are on the whole found to be more effective than voluntary or partnerships at achieving health objectives, but are often not the most politically or commercially acceptable approach. Voluntary approaches and partnerships can also be effective, but studies indicate that they are often based on vague commitments, focused on easy but ineffective approaches, and often hampered by limited monitoring and reporting, generating poor data._x000D_ _x000D_ OBJECTIVES_x000D_ (1) to systematically review the effectiveness of population interventions to improve diet, including mandatory interventions, voluntary mechanisms and public-private partnerships; (2) to conduct a stakeholder workshop on the findings and potential change strategies needed, to advance population interventions to improve diet in England; (3) to share findings in scientific, policy and public forums to maximise the study’s impact._x000D_ _x000D_ METHODS_x000D_ (1) a systematic review of the literature covering how such policy interventions should work in theory, how they have worked in practice and whether they have been effective; and (2) a stakeholder workshop to explore findings and discuss how improvements to population interventions for diet in England can be made, in light of the findings._x000D_ _x000D_ TIMELINES FOR DELIVERY_x000D_ The systematic review will be finalised by end October 2021, the stakeholder workshop, by February 2022, and reporting and dissemination from July 2020 onwards. _x000D_ _x000D_ ANTICIPATED IMPACT AND DISSEMINATION_x000D_ Knowing which population interventions on diet work and how to improve them will help reduce the overall disease burden in the UK, diet-related inequalities and NHS costs._x000D_ Peer-reviewed publications, policy reports and conference presentations will be prepared on the research findings and workshop proceedings and conclusions. Policy and practice recommendations will be formulated for improving the design and delivery of population intervention to improve diet in England, and specifically any recommended alterations to existing policies, how much they might cost, and how cost effective they are estimated to be.

Research activity codes: 3.1 PRIMARY PREVENTION INTERVENTIONS TO MODIFY BEHAVIOURS OR PROMOTE WELL-BEING
Health categories: CANCER AND NEOPLASMS;CARDIOVASCULAR;METABOLIC AND ENDOCRINE;ORAL AND GASTROINTESTINAL;STROKE