Adherence to the Mediterranean Diet, Five-Year Weight Change, and Risk of Overweight and Obesity: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies.

Findings from earlier studies on the association between adherence to a Mediterranean diet and risk of overweight/obesity were inconsistent. We summarized cohort studies investigating the association between the Mediterranean diet and risk of overweight and/or obesity and weight change in adults. A systematic search of PubMed, Scopus, ISI Web of Science, and Google Scholar was conducted up to May 2021. Prospective cohorts that examined the Mediterranean diet adherence in adults as the exposure, and overweight and/or obesity or weight change as the outcomes, and reported RRs or β coefficients and 95% CIs as the effect sizes were included. Seven prospective cohort studies were included of which 6 studies (with 244,678 adult participants) reported the risk of overweight and/or obesity, and 4 cohorts (with 436,617 participants) reported the weight change (3 cohorts reported both overweight and/or obesity risk and weight change). Combining 15 effect sizes from 6 cohorts revealed that greater adherence to the Mediterranean diet was significantly associated with a 9% decreased risk of overweight and/or obesity (RR: 0.91; 95% CI: 0.88, 0.94; I2 = 44.7%; PQ-test = 0.031). This association was significant in the case of studies investigating combined overweight and obesity (RR: 0.92; 95% CI: 0.88, 0.96; I2 = 29.4%; PQ-test = 0.166), but not for studies that reported on obesity (RR: 0.68; 95% CI: 0.43, 1.10, I2 = 50.6%, PQ-test = 0.132). Linear dose-response analysis of 6 studies showed a 2% decreased risk of overweight and/or obesity for 1 additional Mediterranean diet score (RR: 0.98; 95% CI: 0.96, 0.99). Each unit increase in the Mediterranean diet score was associated with 0.04 kg less weight gain over 5 y (-0.04 kg; 95% CI: -0.07, -0.02 kg; 13 effect sizes from 4 cohorts). In conclusion, Mediterranean diet adherence is inversely associated with risk of overweight and/or obesity as well as 5-y weight gain and thus has practical importance for public health.