High Adherence to the Mediterranean Diet is Associated with Higher Physical Fitness in Adults: a Systematic Review and Meta-Analysis.

Although prior research has synthesized the relationships between the Mediterranean diet (MD) and components of physical fitness (PF) in adults, they are limited and inconclusive. This study aimed to synthesize the associations between high (vs. low) MD adherence and PF levels along with each of its components (cardiorespiratory, motor, and musculoskeletal) in adulthood. We conducted a systematic search in five databases from inception to January 2022. Observational studies and randomized controlled trials (RCTs) were included. Pooled odds ratios (ORs) and effect sizes (Cohen's d index) with their 95% CIs were calculated using a random-effects model. A total of 30 studies (19 cross-sectional in young, middle-aged, and older adults, 10 prospective cohort in older adults, and one RCT in young adults) involving 36,807 individuals (mean age range: 20.9-86.3 years) were included. Pooled effect sizes showed a significant cross-sectional association between higher MD adherence scores (as a continuous variable) and overall PF (d = 0.45; 95% CI: 0.14, 0.75; I2 = 91.0%; n = 6). The pooled ORs from cross-sectional data showed that high adherence to MD was associated with higher cardiorespiratory fitness (OR = 2.26; 95% CI: 2.06, 2.47; I2 = 0%; n = 4), musculoskeletal fitness (OR = 1.26; 95% CI: 1.05, 1.47; I2 = 61.4%; n = 13), and overall PF (OR = 1.44; 95% CI: 1.20, 1.68; I2 = 83.2%; n = 17) than low adherence to MD (reference category = 1). Pooled ORs from prospective cohort studies (3-12-year follow-up) showed that high adherence to MD was associated with higher musculoskeletal fitness (OR = 1.20; 95% CI: 1.01, 1.38; I2 = 0%; n = 4) and overall PF (OR = 1.14; 95% CI: 1.02, 1.26; I2 = 9.7%; n = 7) than low adherence to MD (reference category = 1). Conversely, no significant association was observed between MD and motor fitness. High adherence to MD was associated with higher PF levels, a crucial marker of health status throughout adulthood.