Every time you sit down for a meal, you are part of a food system—the chain from production through distribution to your plate and disposal of leftovers. Most of the time, people only focus on the near end of that chain: what to eat today. October 16 is World Food Day, a day to think bigger. Food systems are crucial to achieving most of the 17 Sustainable Development Goals (SDGs), as well as multiple other goals and commitments, such as those on climate change. Currently, many food systems do not function well and some actors within the food system are even actively working against these objectives. Therefore, we need science-driven food transformation. 

3ie believes that research will continue to play a vital role in food systems transformation as it can support policymakers, experts, and stakeholders to make evidence-informed decisions based on what works, for whom, and at what cost. Our Food Systems and Nutrition Evidence Gap Map (EGM) shows where evidence is available and where new research is needed to fill evidence gaps regarding the impacts of food systems interventions. Building this evidence base will support promising interventions being implemented that improve nutrition through food system transformation. 

This EGM on Food Systems and Nutrition is the largest one created so far, and the first living EGM

EGMs systematically collate available evidence, identify gaps, and support the production of new evidence where needed. With support from BMZ through its GIZ-implemented program “Knowledge for Nutrition” (K4N), we launched this EGM on Food Systems and Nutrition in early 2021. It includes all impact evaluations and systematic reviews of impact evaluations published since 2000 within the food system which consider food security and nutrition outcomes in low- and middle-income countries. In all, 1,838 impact evaluations and 178 systematic reviews are included in our largest-ever EGM. 

The literature base on food systems is rapidly increasing. To ensure the EGM remains up to date and relevant for policymakers, experts and stakeholders, we will search for, screen, and add eligible new studies every three months until March 2023. By doing this, we will ensure the EGM continues to provide the most recent scientific literature, especially evidence that emerges from calls to action and influential events such as last month’s UN Food Systems Summit, including its Science Days and the upcoming Nutrition for Growth Summit. We will also analyze and publish regular updates on publication trends, with particular attention to any evidence gaps that might have been recently filled. To our knowledge, this is the first living Evidence Gap Map that will be regularly maintained for an extended period of time.

Areas for future research 

Through the systematic process of creating the EGM, we were able to identify where there are well-researched interventions and where research gaps remain. Some key areas where future research should focus are outlined below. They are ordered based on interest expressed during various stakeholder engagement activities. 

Few studies examined interventions supporting or measuring women’s empowerment within the food system. Women experience significant vulnerabilities within the food system and have the possibility to drive positive change. As such, investment in interventions to support women’s empowerment are increasing. Within this context, gender transformative interventions are prioritized through ongoing discussions such as the Cultivating Equality conference hosted this week. Rigorous impact evaluations of interventions supporting women’s empowerment within the food system are needed to improve intervention efficacy and make the most of these investments. 3ie is currently undertaking a Rapid Evidence Assessment of the limited number of impact evaluations in this field in order to leverage the small existing evidence base. 

Interventions related to governmental manipulations of price and advertising and labelling regulations require additional evaluation. The widespread support of these policies (see here and here) without proper evaluation is concerning given the number of people they affect. Taxes on sugar-sweetened beverages and labelling regulations for unhealthy foods have not been evaluated for their impacts on weight. Despite this lack of evidence, more than 40 countries (including low- and middle-income countries) tax sugar-sweetened beverages. Several countries, including Brazil, China and Thailand, have adopted labelling regulations (for more, see here and here). We will also be conducting a Rapid Evidence Assessment on the impacts of governmental manipulations of price. 

More work needs to consider the impacts of interventions within the food system on nutrition and climate. The food system is a major contributor to global warming as well as malnutrition. Food systems transformation may reduce carbon emissions, especially from the high-income countries, while improving access and affordability of healthy diets for more people, especially the most vulnerable. Although calls for this transformation are increasing, action has been slow. 

Finally, we need systematic reviews which analyze the effects of educational efforts within the food supply chain vis-a-vis nutrition and health outcomes. Educational initiatives are often considered more sustainable than direct support interventions due to a belief that their impacts continue after the interventions end. A substantial number of impact evaluations have been done in this area, but synthesis is lacking. We must evaluate whether these interventions work in general and in what context, beyond whether they worked once.  Synthesis of all the evaluations which have been conducted can help answer these questions. 

Beyond the above, these selected interventions have not been sufficiently evaluated:

• On-farm, post-harvest processing 
• Interventions to support food packaging 
• Innovative store design 
• Cold chain storage 

These additional outcomes have not been sufficiently included in evaluations:

• Economic, social, and political stability 
• Food loss 
• Measures of diet insufficiency 

These areas are lacking syntheses of existing impact evaluations:

• Agricultural extension and information-sharing activities within the food value chain 
• Provision of free or reduced-cost farm inputs to crop production 
• Agricultural insurance products 
• Outcomes related to other dietary measures

For more details on all of the points above, see the interactive Evidence Gap Map, the full report about the EGM, and the brief summarizing the findings.