Background Small Island Developing States (SIDS) are commonly burdened by high rates of nutrition related non-communicable diseases, micronutrient deficiencies, and, in many, persistent childhood stunting. Most of these issues are related to dietary changes, driven by food systems increasingly dominated by global markets and products and vulnerable to environmental and economic threats. This has caused an urgent need for strengthening local food systems, resilient to climate change. We aimed to systematically review evidence on interventions intended to improve diet in SIDS and assess the impact of those adopting a local food approach.

Methods The systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses framework. The search strategy included studies published since 2000 and was applied to eleven databases, including those related to health, social science, and agriculture. Screening of titles, abstracts, and data extraction was undertaken in duplicate; risk of bias was assessed using appropriate Cochrane tools. The results were narratively synthesised. The study protocol was registered: PROSPERO 2020 CRD42020201274.

Results From 26,062 unique records, 154 underwent full-text review and 24 were eligible for inclusion. Eligible studies were from the Caribbean, Pacific, Mauritius, and Singapore. Five were of a randomised study design, one an interrupted time series analysis, eight controlled pre and post-test, and ten uncontrolled pre and post-test. Nine of the 24 studies included a local food approach with eight including the promotion of locally produced food or traditional dietary behaviours, while one examined the unique nutritional composition of local food in their outcome measure of nutrient intake. Five of these nine studies included a practical food production component, such as teaching skills for planting and harvesting own produce. Of the eight studies that included an aspect of ‘local’, four showed significant improvements in dietary intake and nutrition knowledge, two of the four being garden-based nutrition education interventions, supplemented with practical skills components. Only three studies met the criteria for low risk of bias, with 13 being at moderate risk.

Conclusion There is an overall lack of robust evidence on interventions to improve diet in SIDS. The existing evidence suggests that multifaceted interventions applying a local food approach are likely to be effective. Given the issues related to adapting globalised food systems, further development and evaluation of interventions incorporating increased production and consumption of local food is urgently needed to help guide policy.