An Evidence-Based, Multidimensional Definition of the Mediterranean Diet Within the Italian National Guidelines "La Dieta Mediterranea"

The Mediterranean Diet (MD), first conceptualized by Ancel Keys in the 1950s, is widely acknowledged as a dietary pattern associated with significant health benefits. It is also a cultural heritage, recognized by UNESCO in 2010. Despite its relevance, the MD has been variably defined through descriptive models, food pyramids, and adherence scoring systems. This heterogeneity limits comparability across research and practice. This paper describes the development of a standardized, evidence-based, and multidimensional definition of the MD within the Italian National Guidelines “La Dieta Mediterranea." Importantly, the proposed definition integrates both nutritional components and sociocultural dimensions, including lifestyle practices, conviviality, and sustainability. The guideline development process followed internationally recognized standards, involving a multidisciplinary panel and systematic evidence synthesis. The MD was defined conceptually through an operational approach based on the analysis of existing adherence scores available in the literature. Thirty-three eligible studies and fifteen Mediterranean Diet Scoring Systems were analyzed to identify common food groups, nutrients, and lifestyle components. The proposed definition emphasizes high consumption of plant-based foods, olive oil as the primary fat source, moderate intake of fish, dairy, and white meat, and limited consumption of red meat and processed products. Beyond nutrition, the MD is conceptualized as a multidimensional lifestyle encompassing physical activity, conviviality, and sustainability principles. This integrated approach aligns with contemporary evidence on chronic disease prevention and health promotion. The resulting definition provides a conceptual framework for healthcare professionals, researchers, and policymakers, supporting harmonized interventions and policy strategies that extend “beyond the plate."