Shaping sustainable healthy diets discourse on Facebook: A multi-region investigation of urban stakeholders' communication, social networks and public engagement

Effective communication about sustainable healthy diets (SHDs) is a key step to facilitate sustainable transformation of the urban food systems in the context of rapid urbanization and climate change crisis. Based on the theory of agenda setting in social media, this study aimed to answer (RQ1) Who are the key urban stakeholders that communicated SHDs and what is their agenda? (RQ2) What strategies did they use and the effectiveness with user engagement? And (RQ3) How did SHDs promotion connect different stakeholders? 38,004 Facebook posts from 7938 public pages mentioning SHDs across four regions from 2019 to 2022 were retrieved for empirically evaluating their agenda setting. For RQ1, we identified 11 categories of stakeholders and 10 major topics. The topic for supporting local food system development, which aligned with key developmental strategies of sustainable urban food systems, was most salient. For RQ2, we found that the emotional appeals of anticipation, trust, and fear received greater user engagement. For RQ3, the network analysis highlights that participation by local government and non-government organizations leads to better network connections. This study provides insights into the sustainable transformation of urban food systems and effective communication strategies for promoting civil engagement in the transformation processes.