Dietary patterns associated with obesity outcomes in adults : an umbrella review of systematic reviews

Objective: The aim of this umbrella review was to summarize the evidence from existing systematic reviews on the association between different dietary patterns and overweight or obesity outcomes in adults. Design: We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, and searched the MEDLINE, EMBASE, CINAHL, Cochrane, Scopus, and Web of Science for systematic reviews reporting on dietary patterns and weight gain or overweight/obesity outcomes. Result: We identified 16 systematic reviews with 143 unique studies published between 2001 and 2019. Overall quality scores ranged from four to 10. Six reviews in 2/11 cohort and 6/19 cross-sectional studies reported (statistically significant) decreased odds ratios (ORs) for obesity (range: 0.53 to 0.73 and 0.35 to 0.88, respectively) associated with the Mediterranean diet. Five reviews in 5/15 cohort and 10/45 cross-sectional studies reported an inverse association between diet quality and weight gain or body mass index (β range: -1.3 to -0.09). Two reviews in 1/3 cohort and 1/2 cross-sectional studies reported a decreased risk of obesity (OR=0.76) and weight gain (OR=0.26), respectively, with fruit and vegetable intake. Five reviews of mixed dietary patterns in 3/40 cross-sectional studies reported an increased prevalence of obesity (OR=1.19) or abdominal obesity (OR range: 1.07 to 1.27) with the Korean diet pattern. Conclusions: Our umbrella review confirms the hypothesis that Mediterranean-type dietary patterns reduce the risk of obesity in adults. Although population-specific evidence of effective interventions is needed, characteristics of Mediterranean-type dietary patterns are important considerations for national obesity prevention strategies.