Objective: To progress nutrition policy change and develop more effective advocates, it is useful to consider real-world factors and practical experiences of past advocacy efforts to determine the key barriers to and enablers of nutrition policy change. The present review aimed to identify and synthesize the enablers of and barriers to public policy change within the field of nutrition.Design: Electronic databases were searched systematically for studies examining policy making in public health nutrition. An interpretive synthesis was undertaken.Setting: International, national, state and local government jurisdictions within high-income, democratic countries.Results: Sixty-three studies were selected for inclusion. Numerous themes were identified explaining the barriers to and enablers of policy change, all of which fell under the overarching category of ‘political will’, underpinned by a second major category, ‘public will’. Sub-themes, including pressure from industry, neoliberal ideology, use of emotions and values, and being visible, were prevalent in describing links between public will, political will and policy change.Conclusions: The frustration around lack of public policy change in nutrition frequently stems from a belief that policy making is a rational process in which evidence is used to assess the relative costs and benefits of options. The findings from the present review confirm that evidence is only one component of influencing policy change. For policy change to occur there needs to be the political will, and often the public will, for the proposed policy problem and solution. The review presents a suite of enablers which can assist health professionals to influence political and public will in future advocacy efforts.

Influencing public policy change can be difficult and complex, particularly for those with limited power and resources. For any one issue there may be several groups, including the commercial sector and public health advocates advocating from different policy perspectives. However, much of the public health advocacy literature and tools available for those wanting to improve their practice is based on research from one specific perspective of an issue. This approach deprives advocates of potential insight into the most effective levers for this complex and difficult process. To provide a more comprehensive insight into effective levers for influencing public health policy change, a conceptual model for poorly-resourced advocates was developed. The model was developed through the integration and synthesis of policy process and network theories with the results from three studies conducted previously by the authors: a systematic literature review; a social network analysis of influential actors in Australian nutrition policy; plus in-depth interviews with a sample of these actors who had diverse perspectives on influencing nutrition policy. Through understanding the key steps in this model advocates will be better equipped to increase political and public will, and affect positive policy change.

Objective: Junk-food marketing contributes significantly to childhood obesity, which in turn imposes major health and economic burdens. Despite this, political priority for addressing junk-food marketing has been weak in many countries. Competing interests, worldviews and beliefs of stakeholders involved with the issue contribute to this political inertia. An integral group of actors for driving policy change are parliamentarians, who champion policy and enact legislation. However, how parliamentarians interpret and portray (i.e. frame) the causes and solutions of public health nutrition problems is poorly understood. The present study aimed to understand how Australian parliamentarians from different political parties frame the problem of junk-food marketing.Design: Framing analysis of transcripts from the Australian Government’s Parliamentary Hansard, involving development of a theoretical framework, data collection, coding transcripts and thematic synthesis of results.Settings: Australia.Participants: None.Results: Parliamentarian framing generally reflected political party ideology. Liberal parliamentarians called for minimal government regulation and greater personal responsibility, reflecting the party’s core values of liberalism and neoliberalism. Greens parliamentarians framed the issue as systemic, highlighting the need for government intervention and reflecting the core party value of social justice. Labor parliamentarians used both frames at varying times.Conclusions: Parliamentarians’ framing was generally consistent with their party ideology, though subject to changes over time. This project provides insights into the role of framing and ideology in shaping public health policy responses and may inform communication strategies for nutrition advocates. Advocates might consider using frames that resonate with the ideologies of different political parties and adapting these over time.

Summary: Generating political commitment for ending all forms of malnutrition represents a key challenge for the global nutrition community. Without commitment, the policies, programs, and resources needed to improve nutrition are unlikely to be adopted, effectively implemented, nor sustained. One essential driver of commitment is nutrition actor network (NAN) effectiveness, the web of individuals and organizations operating within a given country who share a common interest in improving nutrition and who act collectively to do so. To inform new thinking and action towards strengthening NAN effectiveness, we use a systems dynamics theoretical approach and literature review to build initial causal loop diagrams (CLDs) of political commitment and NAN effectiveness and a qualitative group model building (GMB) method involving an expert workshop to strengthen model validity. First, a “nutrition commitment system” CLD demonstrates how five interrelated forms of commitment—rhetorical, institutional, operational, embedded, and system‐wide—can dynamically reinforce or diminish one another over time. Second, we present CLDs demonstrating factors shaping NAN effectiveness organized into three categories: actor features, resources, and capacities; framing strategies, evidence, and norms; and institutional, political, and societal contexts. Together, these models generate hypotheses on how political commitment and NAN effectiveness could be strengthened in future and may provide potential starting points for country‐specific conversations for doing so.