The relationship between adherence to the Mediterranean diet (MD), physical activity (PA), sedentary behaviour and physical fitness levels has been analysed in several studies; however, there is mixed evidence among youth. Thus, this study aimed to meta-analyse the associations between adherence to the MD, PA, sedentary behaviour and physical fitness among children and adolescents. Three databases were systematically searched, including cross-sectional and prospective designs with a sample of healthy youth aged 3–18 years. Random effects inverse-variance model with the Hartung–Knapp–Sidik–Jonkman adjustment was used to estimate the pooled effect size (correlation coefficient (r)). Thirty-nine studies were included in the meta-analysis, yielding a total of 565 421 youth (mean age, 12·4 years). Overall, the MD had a weak-to-moderate positive relationship with PA (r 0·14; 95 % CI 0·11, 0·17), cardiorespiratory fitness (r 0·22; 95 % CI 0·13, 0·31) and muscular fitness (r 0·11; 95 % CI 0·03, 0·18), and a small-to-moderate negative relationship with sedentary behaviour (r –0·15; 95 % CI –0·20, –0·10) and speed–agility (r –0·06; 95 % CI –0·12, –0·01). There was a high level of heterogeneity in all of the models (I2 ≥ 75 %). Overall, results did not remain significant after controlling for sex and age (children or adolescents) except for PA. Improving dietary habits towards those of the MD could be associated with higher physical fitness and PA in youth, lower sedentary behaviours and better health in general.

几项研究分析了坚持地中海饮食 (MD)、身体活动 (PA)、久坐行为和身体健康水平之间的关系；然而，青年人的证据喜忧参半。因此，本研究旨在荟萃分析儿童和青少年坚持 MD、PA、久坐行为和身体健康之间的关联。系统地搜索了三个数据库，包括以 3-18 岁健康青年为样本的横断面和前瞻性设计。使用 Hartung–Knapp–Sidik–Jonkman 调整的随机效应逆方差模型来估计合并效应大小（相关系数（r)). 荟萃分析中纳入了 39 项研究，共纳入 565 421 名青年（平均年龄 12·4 岁）。总体而言，MD 与 PA ( r 0·14; 95 % CI 0·11, 0·17)、心肺健康 ( r 0·22; 95 % CI 0·13, 0· 31) 和肌肉健康 ( r 0·11; 95 % CI 0·03, 0·18), 以及与久坐行为的小到中度负相关 ( r –0·15; 95 % CI –0·20, –0·10) 和速度–敏捷性 ( r –0·06; 95 % CI –0·12, –0·01)。所有模型都存在高度异质性 ( I 2≥ 75 %)。总体而言，除 PA 外，在控制性别和年龄（儿童或青少年）后，结果并不显着。改善 MD 的饮食习惯可能与年轻人更高的身体健康和 PA、更少的久坐行为和更好的健康状况有关。