Ultra-processed food and the risk of overweight and obesity: a systematic review and meta-analysis of observational studies.

Numerous studies have reported the association of ultra-processed foods with excess body weight; however, the nature and extent of this relation has not been clearly established. This systematic review was conducted to analyze the currently documented evidence regarding the association between ultra-processed food with overweight and obesity. A literature search was performed using multiple literature databases for relevant articles published prior to November 2019. Random effects model, namely the DerSimonian–Laird method, was applied to pool effect sizes. The potential sources of heterogeneity across studies were explored using the Cochrane Q test. Fourteen studies (one cohort study and thirteen cross-sectional studies) were included in this review. A significant association was identified between ultra-processed food intake and overweight (pooled effect size: 1.02; 95% confidence interval (95% CI): 1.01, 1.03, p < 0.001) and obesity (pooled effect size: 1.26; 95% CI: 1.13, 1.41, p < 0.001). Our findings revealed a positive association between ultra-processed foods and excess body weight. Future studies with longitudinal designs and adequate control for confounding factors are required to clarify whether ultra-processed food intake alters anthropometric parameters and leads to obesity.