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Guiding Principles for translating evidence on diet shift for people in the real world

Identify who needs to see your evidence and understand their needs

Understanding who your evidence will be of interest to, and who has the power to act on it, is an important way to ensure evidence leads to action.

A first step is to understand which actors have a role in influencing diet shift, and which ones your evidence relates to, including establishing who is responsible for what. The second step is to understand their needs, and what might influence whether they adopt your evidence. 

Identifying relevant evidence users

The food system is a complex system of activities involving many different actors whose activities can have an influence on diets(footnote).  Actors across the public sector (government and professional practitioners), private sector (commercial food businesses) and third sector (NGOs and community groups) all play a role in creating and delivering policy and practice that influences diet. Healthy sustainable diet shift also involves multiple food system outcomes, including both human health and planetary health. Health and sustainability issues may be dealt with by different departments or organisations, or different individuals or groups within departments or organisations(footnote).  Within an organisation, there may be a dedicated individual or department or a number of different individuals or departments, responsible for evidence gathering. Crucially, these individuals or departments may not necessarily share evidence with one another. 

Identifying policy evidence users

Food policy is made by multiple government departments and agencies. One review identified as least 16 departments with relevance to food systems, many of which will be relevant for diet shift more specifically(footnote).  The departments which hold the levers to take action on the issue your evidence is addressing may not be the most obvious food-related departments. There are limited formal mechanisms in place to ensure food issues and activities are connected across government, and you should not assume that connections on particular policy issues are being made by all the relevant actors, or that sharing of evidence is taking place between different departments(footnote).  For example, stakeholders called on to provide evidence to policymakers have reported delivering the same evidence multiple times to different departments, which were unaware of activities taking place elsewhere in government(footnote).  Along with responsibilities being shared between government departments, food policy is also made at different levels of government. 

Table 5, in the Appendix, maps some of the key diet shift actors to consider, though which are in a position to use your evidence will depend on the issue being addressed and the action to be implemented. 

Who exactly are policymakers?

The term ‘policymakers’ is used as a homogeneous catch-all, but in reality this term encompasses a range of different roles. For one, it can be used to refer to both elected officials like members of parliament and unelected officials like civil servants. It also encompasses a range of different roles within government departments, which can be broadly divided into analysts (for example economists, statisticians, and social and operational researchers who develop the evidence base for policy) and policy officials(footnote).  Research by the Institute for Government has highlighted evidence barriers exist between the different roles: for example, some policy officials see engaging with evidence as the job of analysts (who have good connections and an understanding of academic methods), but because analysts are not well integrated into policymaking they cannot contribute effectively to policymaking(footnote)

Identifying practitioners evidence users

The same considerations on the range of possible users hold true for practitioners. There are many on-the-ground actors involved in food systems and some of the key actors you may want to consider are listed in Table 4 in the Appendix. Practitioners that are relevant for actioning the evidence you have produced will depend on the specific issue being addressed and the action to be implemented. A couple of considerations to keep in mind are that individual organisations may be best accessed through evidence brokers and that health and sustainability issues are not always addressed by the same users, for example some organisations have both net zero and health diet teams who still work in silos and may require evidence to be delivered separately. 

“Diet and environment are managed by different individuals and teams and this topic needs integration. So diet and health managers need to work with net zero managers.” – Food Industry Trade Association

“Recently we have brought together under the same policy unit our teams who work on nutrition, climate and food poverty to create a more systems approach to these related issues.” – Food Retailer

Identifying end-users, the What Works Approach

The What Works approach to identifying end-users may provide some useful ideas on how to identify the type of users you want to target. Each issue-specific Centre within the What Works Network has its own defined ‘audience’ for its outputs, and they vary in how ‘users’ are defined, on:

  • which potential users are prioritised (and which are not)
  • how tightly these users are specified
  • the relative emphasis on individuals, groups or organisations
  • the emphasis on engaging early adopters/champions or a broader audience
  • the distinction between the users of Centres outputs and services and the ultimate beneficiaries of the Centres’ work
  • equity issues of differential engagement with both the use and production of research.(footnote) 

Understanding the drives and needs of different diet shift actors

After identifying which actors your evidence is relevant to, the next step is to ensure you understand them, in order to demonstrate:

1)    Why they should care about your evidence; and 
2)    What actions they might be able to take on it. 

Users are more receptive to evidence when it is relevant to their interests and priorities(footnote).  There is a common desire from users that evidence is sector specific, tailored specifically to different food system actors and accounting for their different priorities and needs. Successful communication also means empathising with your target audience, ideally from the start of the evidence-gathering process(footnote).  This requires an understanding of what influences someone’s ability and motivation to act, such as the political and social context, resource (including time) constraints and what their evidence needs are(footnote).  

One important distinction to be aware of is between the needs of policymakers and practitioners. While these two types of evidence user are often treated as a single group, their needs - including their incentives for taking action on diet shift - may be quite different(footnote).  Understanding policymaking, and the role of politics, are crucial for generators wishing to influence policy, and are addressed separately below. Another important difference to be aware of is between types of practitioner, for example professional versus commercial practitioners. In the literature on evidence-use, the practitioner category is dominated by public sector professionals, such as health and education providers. This makes sense if there is a natural alignment between government objectives (for example educational policy objectives) and public sector practitioner objectives (for example teaching practitioner objectives). However, treating commercial practitioners as part of this same group is problematic: the relationship between public policy, or broader social objectives, and commercial practitioner objectives is more complex, and there is potential for conflict between policy objectives (for example, make people healthy) and private sector objectives (such as sell food products). 

Depending on the kind of evidence you are producing, you may also need to think about the needs of different users simultaneously. For example, understanding the needs of policymakers involves understanding the needs of the stakeholders that policy is relevant to (and which any policymaker will need to bear in mind when acting on evidence). This may involve demonstrating an awareness of the public acceptability of any recommended policy actions, and also among supply chain actors, or the on-the-ground practicalities of particular policy actions. This is particularly the case if policymakers will depend on businesses to implement a policy action. 

Two universal recommendations applicable across all evidence users are: 1) to make evidence ‘food-system specific’, for example, evidence on carbon cost accounting and net zero goals; and 2) to understand the role other food system actors play in their capacity to act. For example, retailers and restaurants report being heavily reliant on the advice given by, and products available from, their suppliers. In the same way, the actions available to food banks can be limited by their membership of an overarching network with its own philosophy and practice rules, such as the Trussell Trust. The following insights - drawn from the literature and direct from evidence users - detail some of the needs of particular actor groups. Groups are included where particular evidence on them was available and some groups are not therefore included. Policymakers are addressed separately in a dedicated section below.

Commercial practitioner evidence users...

  • are likely to have a primary objective around the profitability and reputation of their business
  • are concerned about public perception and what their customers want/need
  • may be operating with small margins
  • may not wish to act on evidence because it could put them at a competitive disadvantage compared to other businesses which are not taking action. For this reason commercial practitioners may express a preference for more legislation around healthy sustainable diets to create a ‘level playing field’
  • may not wish to share evidence on their activities because they are commercially sensitive and may be used by their competitors
  • may prefer group-based evidence-generation methods – such as workshops, roundtables – to be on an anonymous basis, for example under Chatham House rules, or one-to one anonymous methods such as interviews, due to commercial sensitivity
  • are interested in what their peers are doing and whether it is working
  • may be generating their own evidence on a particular issue or intervention
  • may have multiple divisions and roles, meaning your evidence has to be delivered to multiple places in order to effect action
  • also need to consider the messaging of evidence to their customers, and this may require working with respective communications teams to ensure the messages are translated effectively

"Researchers don't always understand how complicated it is implementing new policy in a business like ours. We have thousands of staff with different responsibilities and targets which sometimes are in tension. We have buyers who are paid on the margin they create and we have other functions that are targeted on reducing our social and environmental footprint." – Food Retailer

Health practitioner evidence users...

  • have limited actions they can take on healthy sustainable diets other than providing information to citizens
  • may not be trained in nutrition
  • may not perceive ‘sustainability’ as relevant to health and be unfamiliar with sustainability concepts and principles
  • may refer advice about healthy diets on to specialist organisations, including special units on weight management
  • have little time to search for evidence themselves and rely on evidence brokers (for example, management, government bodies and public health networks) to relay information

Third sector evidence users...

  • may be constrained in the actions they take based on what funding is available
  • may be constrained by the impacts - including financial - of any action on citizens, in particular disadvantaged citizens
  • may be constrained in what action they can take by membership of an overarching network which sets guidelines on their activities
  • may be constrained by scale of operation – for example they work within a specific community rather than at a national or regional level
  • if they are working on-the-ground with disadvantaged communities, may have more pressing considerations or immediate actions which are required - for example providing food of any kind - with limited capacity to consider the healthiness or sustainability of that food

“Food is so sticky, it’s so messy and there’s so many people involved. And it [understanding needs] really matters.” – Local Food Partnership

Understanding policymaking and the role of politics

Evidence generators are regularly exhorted to ensure their research has relevance to and impact on policy. In reality, policymaking often takes place behind closed doors, and can be perceived as a confusing and intimidating terrain for scientists and other stakeholders wanting to engage with it(footnote).

There are multiple aspects of policymaking which evidence generators need to understand to ensure their evidence has the best possible chance of being adopted. These include: 1) who is responsible for what; 2) what policymakers can do; 3) how the policy process works; 4) the role of political priorities; and 5) the role of public acceptability. 

Understanding what policymakers can do

At its most basic level, understanding policymaking means understanding what action policymakers themselves can actually take. There is a relatively limited range of things policymakers can do: which can be boiled down to the ability to exhort, legislate, and allocate resources (footnote).  When it comes to diet shift, there are a range of different policy levers which can be utilised, and evidence-generators should aim to be aware of what is possible and whether it is effective when recommending particular policy actions(footnote).  Evidence generators have a tendency to overestimate the food policy levers which reside at local government level, for example(footnote).  Linked to this point, another consideration is that policymakers themselves do not hold all of the levers for change, and rely heavily on on-the-ground actors to implement actions. This may involve thinking about the implementation/delivery process, and which actors may need to be involved (and may therefore need to be considered when generating and translate your evidence).

“One of the things to understand really about local decision-making is that it needs to have levers that are relevant to its identity and where it sits...You've got to be mindful that we have different levers in different places, and that's what I meant about the appropriateness of the evidence.” – Local Government Actor

Understanding the policymaking process

Along with understanding what policymakers have the power to actually do, evidence generators should have some knowledge of how the process of policymaking process. Researchers often have an idealised understanding of policymaking as a linear and predictable process(footnote), an image which is perpetuated by the notion of a ‘policy cycle’ of evidence-based activities from: agenda setting; formulation; adoption; implementation; evaluation; to support/maintenance. In practice, policymaking is more messy, complicated and non-linear(footnote), and there are many factors other than evidence provision which influence policy(footnote) (see Box 6 below). While this reality exists across policy issues or fields, these characteristics are argued to be particularly pronounced in the case of diet shift evidence because food systems are inherently complex and wide-reaching(footnote).  By understanding the realities of this process, you can more strategically provide evidence(footnote)

Factors other than evidence which influence policymaking

The supply of evidence is only one factor which influences why evidence is adopted, and the policy sciences literature has a long history of identifying many other factors which influence policy, which include: 

  • the experience, expertise and judgement of policy officials and ministers; 
  • values and ideologies; 
  • available resources; 
  • habits and tradition; 
  • lobbyists, pressure groups and the media; and 
  • the pragmatics and contingencies of everyday political life(footnote).  

Another important consideration is that even if evidence is adopted into policy, this may not result in effective implementation. For example, an analysis of obesity policies over the past 30 years highlighted how obesity evidence was not effectively translated and implemented within UK government strategies(footnote)

Understanding the role of political priorities

Evidence which is useful to policymakers explicitly states the policy problem or aspect of a policy problem the evidence addresses. It is important that evidence generators recognise that “a policy problem is not usually the same as a scientific problem, and may have several scientific problems incorporated within it”.(footnote)  Which problems are considered policy problems are influenced by a range of factors (see Box 6 above) and the same is true for potential solutions. Linking evidence to the political priorities of the day and ensuring topics are timely and already of interest to decision-makers(footnote) is one way of improving the likelihood it gets noticed when a political ‘window of opportunity’ is open(footnote). Depending on which kind of policymaker you are trying to deliver evidence to this may involve linking your evidence to current departmental objectives or, in the case of elected officials, thinking about what is relevant to their constituency (for example, does an MP represent a rural constituency with a large agricultural community?), or to voters more broadly. Manifesto commitments are another way to identify political priorities. 

Closely linked to this is how public acceptability influences policy action which may be based on a perception, or the reality, of issue salience with voters. Anticipating the public acceptability of an action your evidence recommends, and acknowledging it, perhaps even proposing additional actions to mitigate, may reduce the possibility it gets discounted outright. Researchers have demonstrated, for example, that packaging up policy interventions which are less popular with the public (for example food taxes), with interventions which are more popular (such as funding healthy activities) may enhance their acceptability(footnote).  

Evidence generators can also link their research to particular political or social developments. Governments declaring a ‘climate emergency’, and the UK’s hosting of the climate conference COP 26 in 2021 are identified by evidence users as useful hooks for generators to attach their evidence to. 

On a more granular level, politics can also shape how research and policy interact: for example, how a government uses external expertise in policy(footnote).  How contentious an issue is may determine whether expert advice or evidence is considered, and the perspectives and values of an individual political actor, such as a minister, can shape the relationship between a department and the academic community (see Box 7).

“Pretty much if you're looking at policymaking, you're looking at about one part evidence and 99 parts political strategy.”  - Local Food Partnership

"Public perception is a big one. There's a really good example, and it's going back a few years…there was a council whose director of public health came in and they did their director of public health report explicitly on climate change. And there was a whole section in there on diet and what the contribution of that was, and that we should be reducing our meat content, and there was a local furore. There was an outpouring… the press, the councillors. It was very poorly landed.” – Regional Public Health Network

Understanding research relationships: How politics shapes evidence use in Whitehall (UK National Government)

Research by the Institute for Government reveals how officials may find it easier to engage with expert advice in less contested areas, where ministers and officials are less likely to have prescriptive government manifesto commitments to stick to, and there are fewer interest groups to consider. In more political areas, evidence and expertise are more likely to be viewed through the lens of a policymaker’s values and what they think will be politically acceptable(footnote).  Political debates – and sometimes individual ministers – can also shape the relationships whole departments have with academic communities. Along with knowing which departments cover which policy issues, having an understanding of a department’s approach to research - for example is it predominantly internally produced or commissioned, does it have a research advisory body - can inform your strategy for dissemination. In the case of the UK Government departments, for example, the Department for Work and Pensions is characterised as having a strong internal research staff but a poor relationship with some parts of the academic community researching social security. The Department for Education has also, at times, had a fractious relationship with the education research community. Departments with strong connections with research communities include the Department for International Development (now incorporated in the Foreign, Commonwealth and Development Office) and Department for Health & Social Care. The Department for Environment Food & Rural Affairs has been building links with the research community through institutional innovations such as its ‘Systems Programme Team’, set-up in April 2018. The DEFRA Chief Scientist’s Office recruited six academics across a range of disciplines to work with six civil service counterparts to embed systems approaches in its policymaking.

Practical examples: Identifying and understanding evidence users

Some resources, and examples, which may be useful for identifying and understanding evidence users include:

  • who Makes Food Policy In England? is a map of government departments with relevance to food systems, which can be utilised to identify who holds the levers for change on particular issues. 
  • the Food And Drink Federation’s Net Zero Handbook gives food businesses a set of practical actions they can take to bear influence on and reduce the embodied emissions of their products at the different points of the Farm to Fork supply chain. “It is in a user-friendly format providing actions on next steps that manufacturers can take regarding emissions incurred at each point of the supply chain, as well as outlining the responsibilities for all different business functions such as HR, Strategy, Sourcing, Operations etc. This is to illustrate how it requires a whole organisation approach. We wanted to provide a guide for those people on the ground who don’t necessarily know what to do.” (Food and Drink Federation)
  • the Institute for Government think tank, and the government’s own National Audit Office, produce reports analysing the workings of government, or on particular departments, which offer a window into policymaking processes and political priorities.


  • are you familiar with the wide range of actors with a role in influencing diet shift, and which ones your evidence relates to?
  • are you aware that health and sustainability issues may be dealt with by different departments or organisations, or different individuals or groups within departments or organisations?
  • does the organisation you are targeting have a dedicated person responsible for evidence, and if not which individuals need to see your evidence? 
  • have you accounted for the fact that government departments, or internal divisions in an organisation or department, may not share evidence with one another?
  • have you considered the different roles which fall under the umbrella term ‘policymaker’?
  • have you made your evidence food-system specific? 
  • have you ensured your evidence is sector specific and tailored to different food system actors?
  • have you considered the differing needs of policymakers vs practitioners?
  • does any policy action indicated by your evidence involve implementation by practitioners, including businesses, and are their needs acknowledged?
  • have you factored in the role other food system actors play in the capacity of particular users to act?
  • do you understand what action policymakers themselves can actually take on the issue your evidence addresses?
  • have you identified whether the levers for change reside with national or local policymakers?
  • have you reflected on the on-the-ground actors which may need to implement policy actions?
  • are you familiar with how policymaking works, and the many different influences other than evidence which influence policymaking?
  • have you stated the policy problem as opposed to the scientific problem that your evidence addresses?
  • can you link your evidence to current political priorities, and/or any political or social events?