Southeast Asian food systems are changing rapidly. Populations are growing and urbanising, production and consumption choices are shifting, and food value chains are experiencing a myriad of ripple effects from rural hinterlands to city marketplaces. These systemic changes are inconsistent, however, and variable challenges define key sectors. Distribution chains, wholesaling, food processing, retail and supermarkets, and other midstream and downstream segments of regional food systems are undergoing transformative and largely unhindered change. On-farm modernisation and trade liberalisation are occurring more haltingly. Previous advances in food production technology and methods have lost momentum, and much of the region faces confronting questions about how to produce adequate and appropriate food in light of shifting demographics, environmental stress, land scarcities, market manipulations and other defining regional characteristics. This paper juxtaposes these challenges with remarkable distribution chain evolutions, and focuses upon three impediments to further shifts in regional food systems: (1) the perpetuation of agrarian mythologies, (2) push-back against rice market integration, and (3) regulatory barriers to the adoption of genetically modified (GM) plants. These seemingly disparate dynamics actually have points of convergence, and are unified in their negative overall impacts on regional food security. This paper explores reasons behind the pervasiveness of these impediments and argues for supply-oriented improvements in the regional food systems.