Proposing a unified Mediterranean diet score to address the current conceptual and methodological challenges in examining adherence to the Mediterranean diet.

A plethora of studies has documented the benefits of the Mediterranean diet (MedDiet) for both human and environmental health. At the core of these investigations lies the assessment of adherence to it. In this manuscript, we aim to examine existing original scores used to assess adherence to the MedDiet and propose a framework for a unified score to address current challenges and complement the existing scores. A literature search was conducted to identify original MED scores, excluding those derived from earlier scores. A total of nineteen original scores were identified and examined. At the conceptual level, across existing scores, the following issues were identified: inconsistencies in food items, lack of holistic lifestyle approaches with focus on food-based components, limited cultural specificity, absence of sustainability evaluations, and regional focus solely on economically developed countries. At the methodological level, the majority of scores were based on cutoffs set by the population-specific distributions of dietary intake. Such cutoffs may be in discordance with the dietary recommendations of the different food groups considered. In addition, the definition of "adherence" is inconsistent across the scores, making the interpretation and comparability of the prevalence of adherence another methodological challenge. As a result, a framework for a Unified Mediterranean diet Score (UMEDS) is proposed. This framework consists of 10 food groups (whole grains, fruits, vegetables, dairy products, fish, legumes, olive oil, nuts and seeds, poultry, and red meat). These food groups are the common denominators of a traditional Mediterranean diet. In addition to the food-related components, the UMEDS also addresses physical activity, sleep, conviviality, and culture-specific food consumption (mainly composite dishes based on olive oil). For each of these items, evidence-based cut-offs were proposed. The total score for the UMEDS ranges from 0 to 22 with higher scores indicating a higher adherence (≤12 poor adherence, 13-17 moderate adherence, ≥18 good adherence). By integrating key components of dietary intake, lifestyle habits, and cultural practices, the UMEDS provides a comprehensive unified approach that aligns with global health guidelines and reflects the true spirit of the Mediterranean diet, rooted in food, lifestyle, culture, lifestyle, and traditional knowledge and practices.