Adherence to Mediterranean Healthy Lifestyle Patterns and Potential Barriers: A Comparative Study of Dietary Habits, Physical Activity, and Social Participation Between German and Turkish Populations

<b>Background/Objectives</b>: Adherence to the Mediterranean Diet (MedDiet) has declined even within Mediterranean regions, while its adoption has become more common in non-Mediterranean contexts. This study compares Germany and Türkiye, two culturally contrasting contexts traditionally classified as non-Mediterranean and Mediterranean, respectively, to examine cross-cultural differences and patterns in MedDiet adherence and related lifestyle behaviors. Specifically, it aims to compare adherence to the Mediterranean lifestyle (MedLife), physical activity, and social participation, and to analyze their associations within each country. <b>Methods</b>: Using data from the MEDIET4ALL survey, 1184 valid responses (609 from Germany and 575 from Türkiye) were analyzed for dietary behaviors, perceived barriers to MedDiet adherence, physical activity, and social engagement, with adherence assessed via the MEDLIFE index. <b>Results</b>: The majority of respondents were healthy (79%), employed (67%), young adults (56%), of normal weight (51%), living in urban environments (72%), and showed a gender balance (52.5% female). Most were classified as medium MedDiet adherent in both Germany (45%) and Türkiye (56%), with no significant difference in total MedLife scores. However, block- and item-level analyses revealed that Turkish participants showed higher adherence to Mediterranean food consumption (<i>p</i> < 0.001), particularly in limiting processed meat and consuming legumes, dairy, nuts/olives, and olive oil. In contrast, German participants adhered more closely to recommendations for red meat and cereal intake. German participants also scored higher on lifestyle-related behaviors (e.g., regular napping and recommended sleep duration), while no significant differences were found in the dietary habits block. Awareness of the MedDiet was significantly higher among German participants (<i>p</i> < 0.001), with country-specific differences in perceived barriers (i.e., higher total score among Germans with <i>p</i> = 0.03). Germans reported more barriers related to social norms and health conditions, while Turkish respondents more often cited attitudes, cost, and individual beliefs. Physical activity levels were significantly higher in Germany, whereas Turkish respondents reported greater social participation (<i>p</i> < 0.001). Weak to moderate correlations (r = 0.09 to 0.035) were found between MedLife adherence and both physical activity and social participation, with stronger associations observed among German participants. <b>Conclusions</b>: These findings highlight the culturally embedded nature of lifestyle behaviors related to MedDiet adherence. Despite similar overall adherence levels, Germans and Turks differ in specific dietary patterns, lifestyle practices, and perceived barriers, underscoring the need for culturally tailored interventions to improve adherence.