Improving the adoption and sustainability of evidence-based policies: A life course approach to reducing diet-related NCDs in adolescents

Lead Research Organisation: University of Cambridge
Department Name: MRC Epidemiology Unit


People, world-wide, are increasingly becoming overweight or obese (OO), even children. Being overweight or obese is a serious health concern and can lead to many diseases (called non-communicable diseases or NCDs) which reduce the quality of one's life or even untimely death. Many of these deaths occur in low- and middle-income countries.

One important contributor to overweight and obesity is eating highly processed foods, often termed 'junk food'. Children who are OO are more vulnerable to developing NCD's and this continues into later in life. Therefore, the World Health Organisation, and other organisations concerned with health, believe that governments should prioritise policies that prevent young people become OO.

In South Africa, the rate of OO amongst children is high compared to countries with similar economic circumstances. Indeed, South African children are at risk of developing high blood pressure or diabetes during childhood and numerous NCD's later in life. While the South African government has taken steps to improve children's health through a sugary beverage tax, and limiting the salt content of food, the problem persists. This shows that food policies are currently not working as they should. It seems that there is a gap in the implementation of those policies. It is therefore important to investigate the nature of this gap.

This study will look at various aspects of South African food policies aimed at decreasing NCD's, to identify the problem, particularly as they effect children aged 10-14 years old and 15-19 years old in an urban and rural province and make recommendations to resolve these gaps.
The study will be conducted over four years (2023-2027), using an existing implementation research tool called the Exploration, Preparation, Implementation, Sustainment (EPIS) framework, which has four phases:

Phase 1 - Exploration: We will review all South African policies aimed at improving diets and in particular those of children.

Phase 2 - Preparation: We will engage with children, policy makers and enforcers as well as parents and other people with an interest to identify the strengths and weaknesses of existing policies, and whether they are being implemented as they should be.

Phase 3 - Implementation: We will then develop intervention strategies to overcome identified weaknesses or harness existing strengths. We will cost these strategies and then with all the key stakeholders rank them in order of priority.

Phase 4 - Sustainability: Finally, we will consider whether these strategies have the potential to be implemented in the long term.

The main outcome of the study is a costed and prioritised list of interventions that will decrease OO of adolescents and decrease NCDs in South Africa.

Technical Summary

The aim of this proposed research is to facilitate effective adoption and sustainable implementation of public policy with the potential to decrease ultra-processed foods (UPF) consumption and diet-related non-communicable disease (DR-NCD) risk among South African adolescents aged 10-19 years old, and across their life-course. An exploratory, sequential study design will be conducted over four-years (2023-2027) in an urban (Gauteng) and rural (Mpumalanga) province, using a combination of quantitative and qualitative research methods. The study will be underpinned by the Exploration, Preparation, Implementation, Sustainment (EPIS) framework for implementation research, highlighting four phases that will guide the research process to meet the research objectives at each phase which are to:

a) Use evidence-based frameworks to map the landscape of national & regional policies with the potential to decrease UPF consumption and DR-NCD risk in South African adolescents (Phase 1 - Exploration);
b) Identify and describe barriers and facilitators to implementation of relevant policies with key stakeholders (Phase 2 - Preparation);
c) Cost and prioritise evidence-based strategies to facilitate implementation of relevant policies (Phase 3 - Implementation); and
d) Assess factors that will influence effective sustainability of implementing the prioritised evidence-based strategies at a national level (Phase 4 - Sustainment).

The main outcome of the study will be potential costed context-specific interventions, selected through multi-stakeholder engagement, including policymakers, community gatekeepers, adolescents, and some food retailers/regulatory representatives. Effective implementation of these should help reduce overweight and obesity in adolescents and overall contribute to the prevention and reduction of NCDs in South Africa across the life-course.


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