Integrating Indigenous Food Knowledge Systems into National Dietary Guidelines: A Participatory Mixed-Methods Study Across Nigeria’s Six Geopolitical Zones

National dietary guidelines in Nigeria have been developed with limited incorporation of indigenous food knowledge systems, traditional food preparation methods, and culturally specific dietary norms, reducing their relevance and uptake across ethnically diverse communities. This study examines how indigenous food knowledge systems can be systematically documented, evaluated, and integrated into evidence-based national dietary guidelines through a participatory process across Nigeria's six geopolitical zones. A transformative mixed-methods design was employed. In Phase 1, ethnobotanical and food systems research methods were used to document indigenous nutritional knowledge, traditional food varieties, preparation practices, and cultural dietary beliefs among 12 purposively selected ethnic communities spanning the six geopolitical zones, through semi-structured interviews, focus group discussions, and participatory food mapping with knowledge keepers, elders, and community nutritionists. Phase 2 analysed the nutritional composition and protective phytochemical content of 40 traditionally significant but underutilised indigenous foods using proximate, micronutrient, and phytochemical analysis. Phase 3 translated findings into draft guideline language through co-design workshops with nutrition policy experts, community representatives, and communication specialists. Consensus validation was conducted using a modified Delphi technique with a national expert panel. Findings will generate an original methodological framework for participatory dietary guideline co-development and produce the first systematic synthesis of indigenous food knowledge systems across all Nigerian geopolitical zones, challenging the epistemological dominance of Western nutritional paradigms in Nigerian food policy. Keywords: indigenous food knowledge, dietary guidelines, participatory research, Nigeria, food culture.