Quoc Nguyen

Food systems in low- and middle-income countries (LMICs) face complex, intraconnected challenges as they transition towards more sustainable futures. Despite notable progress, persistent and emerging problems remain: food safety risks, the triple burden of malnutrition, socio-economic inequities, environmental degradation, and climate change impacts. Overcoming these requires food systems governance to shift beyond single-sector interventions toward more holistic, coordinated approaches capable of pursuing multiple sustainability goals simultaneously. Such coordination is frequently undermined by critical disconnects that operate both horizontally (across production, distribution, and consumption segments) and vertically (between global/national and local scales). This thesis conceptualizes these disconnects as the “Missing Middle.”

The thesis centers on understanding, analyzing, and addressing the Missing Middle in LMIC food systems. It adopts a dynamic perspective, viewing the Missing Middle as embedded within ongoing food system transitions and shaped by interactions among processes at different levels and segments. In analyzing the Missing Middle, the thesis employs two complementary theoretical lenses: Social Practice Theory (SPT), which focuses on micro-level changes in the everyday, routinized practices of food system actors, and Transition Theory - particularly the Multi-Level Perspective (MLP) and Strategic Niche Management (SNM) frameworks - which investigates macro-level dynamics across landscape (external pressures), regime (dominant incumbent systems), and niche (innovation-supporting networks) levels.

The research is based on case studies in Vietnam, with primary empirical fieldwork conducted between 2020 and 2023, mainly in Hưng Yên Province and Hanoi. It examines two major commodity chains, pork and vegetables, that are central to Vietnamese diets and rural livelihoods yet continue to face critical food safety challenges. Multiple methods were deployed to collect and triangulate data, including a scoping review and desk study, semi-structured interviews, survey, observations, and stakeholder consultations. The thesis includes four empirical chapters, focusing on overall food system transitions (Chapter 2), changes in small-scale vegetable (Chapter 3) and pork practices (Chapter 4), and the development and diffusion of agri-food niches (Chapter 5).

Chapter 2 traces the the historical transition of Vietnamese pork and vegetable networks from 1975 to 2019, based on the data extracted from a scoping literature review. It applies the MLP together with the Multi-Pattern Approach (MPA). The MLP identifies decade-scale transition pathways, while the MPA disaggregates these into shorter-term patterns of network enpowerment, contraction, adaptation, or external intervention. The analysis delineates three main phases: (1) the collapse of collective farming and the rise of smallholder production (1975–1992); (2) rapid expansion of smallholders’ production accompanied by the formalization of wet markets (1992–2008); and (3) partial modernization through supermarkets and certification schemes, alongside the continued dominance of traditional distribution networks (2009–2019). The Chapter argues that progress toward improved food safety remains slow and locked in, sustained by strong alignments among actors, practices, infrastructures, and cultural values that reinforce small-scale, fragmented systems.

Chapter 3 explores how vegetable producers and distributors have altered their practices over time, using desk study, interviews, surveys, and observations. Combining SPT and MLP, the analysis zooms in to examine shifts in practice bundles and their core elements (meanings, materials, competences), then zooms out to link these micro-level changes to broader regime and landscape dynamics, identifying key intersection points that block or enable system changes. Contrary to the common notion on few production changes, there are clear transition patterns of production practices: smallholders have increasingly adopted biopesticides, integrated pest management, crop rotation, organic fertilizers, and improved soil cultivation. These shifts arise from converging pressures around food safety concerns, labor shortages, and soil degradation. In contrast, distribution practices exhibit strong inertia, remaining anchored in informal trust-based relations and lacking formal safety controls, even as practices diversify in response to urbanization. The findings highlight that while production-level changes are significant, persistent inertia in distribution continues to obstruct broader systemic transformation.

Chapter 4 examines pork production and distribution practices, with particular attention to biosecurity and food safety. In the same vein as Chapter 3, it deploys SPT and MLP and follows the 'zooming in/zooming out' approach, drawing on desk study, interviews, a survey and observations. Results indicate that producers have substantially strengthened biosecurity measures (disinfection, vaccination, quarantine), driven by a profound shift in meanings where biosecurity became vital for farm survival, along with enhanced access to materials and knowledge sharing. The African swine fever outbreak served as a triggering event that accelerated these changes, yet biosecurity adoption still relies on pre-existing material conditions and producers’ perceptions of fatality and care. Food safety practices, however, evolved unevenly and remained context-dependent, i.e. rural and urban settings. The Chapter underscores that, despite overlapping concerns with hygiene and disease prevention, biosecurity and food safety have followed divergent trajectories, with the latter lacking sustained incentives for change, particularly in distribution practices.

Chapter 5 investigates two certification initiatives, the grassroots Participatory Guarantee Systems (PGS) for organic vegetables and the state-run Vietnamese Good Animal Husbandry Practices (VietGAHP) for safe pork, through interviews and media analysis. Employing the Strategic Niche Management framework, it examines internal niche processes (envisioning, networking, learning) and external diffusion pathways (growth, replication, accumulation, translation). The two initiatives pursue markedly different strategies: VietGAHP relies on time-bound, project-based targets, state centric networks, and technical training, whereas PGS emphasizes long-term organic visions, inclusive stakeholder networks, and reflexive learning. Despite different strategies, both face similar scaling barriers - informal market dominance, institutional fragmentation, and limited consumer familiarity - that constrain their growth and diffusion. The Chapter concludes that state-run initiatives can learn sigificantly from grassroots approaches, especially in reflexive learning and building networks, and that enabling institutional and market environments are necessary for niche expansion beyond initial development.

In the concluding Chapter 6, I synthesized my findings to address the central research question. To deepen the understanding of the Missing Middle, I developed a typology of four Missing Middle mechanisms based on the empirical findings: (i) Hiding: key actors or infrastructure systematically overlooked in policy, exemplified by informal distribution networks; (ii) Blocking: systemic impediments resisting alternative solutions, driven by not only power consolidation but also power fragmentation; (iii) Mismatching: misalignments across divergent interpretations, incompatible institutional logics, and priorities; and (iv) Depleting: absence or erosion of crucial support structures, including limited resources and capacity, and weak coordination among sectors and levels. I also reflected on the uses of the two theoretical lenses – Transition Theory and Social Practice Theory – for analyzing the Missing Middle, with some reflections on their potentials and challenges. Lastly, I analyzed how the Missing Middle can be addressed in LMIC contexts, emphasizing the need for considering non linearity, complexity, and political economy.

Overall, the thesis advances understanding of food system transitions in LMICs by revealing how disconnects emerge through complex interactions across levels and segments. Drawing on the Vietnamese cases, it offers several policy implications: recognizing the roles of smallholders and informal actors, supporting bundled practice changes, aligning values and expectations across sectors and governance scales, and co-developing monitoring and enforcement capacities through strong public–private coalitions. Crucially, the thesis argues that LMIC food systems need not replicate Western modernization trajectories; instead, they can and should pursue inclusive pathways that simultaneously advance healthy diets, environmental sustainability, and socio-economic equity for all food system actors.