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

Nahla Hwalla¹Antonia Trichopoulou²Jacques Delarue³Felice Adinolfi⁴Elliot Berry⁵Furio Brighenti⁶Barbara Burlingame⁷Roberto Capone⁸Sandro Dernini⁸Maroun El Moujabber⁸Marcela Gonzalez-Gross⁹Yari Vecchio⁴Nour Massouh¹Farah Naja^1,10*

• ¹Department of Nutrition and Food Sciences, Faculty of Agricultural and Food Sciences, American University of Beirut, Beirut, Lebanon
• ²Academy of Athens, Athina, Greece
• ³EA7479 Soins primaires, Santé publique, Registre des cancers de Bretagne occidentale (SPURBO), Brest, Brittany, France
• ⁴Department of Veterinary Medical Sciences, University of Bologna, Bologna, Emilia-Romagna, Italy
• ⁵Hadassah Braun School of Public Health and Community Medicine, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Jerusalem, Israel
• ⁶Department of Food and Drug Sciences, University of Parma, Parma, Emilia-Romagna, Italy
• ⁷Riddet Institute, Massey University, Palmerston North, Manawatu-Wanganui, New Zealand
• ⁸International Centre for Advanced Mediterranean Agronomic Studies, Valenzano, Italy
• ⁹Facultad de Ciencias de la Actividad Física y el Deporte, Universidad Politécnica de Madrid, Madrid, Madrid, Spain
• ¹⁰Department of Clinical Nutrition and Dietetics, College of Health Sciences, University of Sharjah, Sharjah, United Arab Emirates

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.