Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 54 9 2025 10 03 1808 1819 Seif Khalfan 1. Food Safety and Health Research Centre, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China 2. Faculty of Health and Allied Sciences, Zanzibar University, Tunguu, Zanzibar Tanzania Jeremie Minani Faculty of Health and Allied Sciences, Zanzibar University, Tunguu, Zanzibar Tanzania Sultan Muki Faculty of Health and Allied Sciences, Zanzibar University, Tunguu, Zanzibar Tanzania Fatma Said Ministry of Health, Zanzibar, Tanzania Dennis Lyakurwa Department of Curative Services, Ministry of Health P.O.Box 743, Dodoma, Tanzania Bo Zhang Food Safety and Health Research Centre, School of Public Health, Southern Medical University, Guangzhou, Guangdong, China 2024 12 15 2025 03 11 Background: The prevalence of obesity and overweight globally has increased to epidemic proportions, representing a substantial burden on health systems. The consumption of high-energy-density but low-nutritional-value food, known as fast food, has been linked to the obesity epidemic. This review aimed to quantify the association between fast food consumption and overweight/obesity in individuals aged ten years and above. Methods: We followed the PRISMA-P 2020 guidelines. To identify studies, English databases, including PubMed, Web of Science, Scopus, Science Direct, and DOAJ, were searched. The search strategy focused on terms and inclusion criteria. After quality assessment, data were analyzed using SPSS software. Results: Thirteen studies out of 665 screened indicate a significant positive association between fast food consumption and obesity or overweight (OR 2.979 [1.748-5.078]). Heterogeneity analysis revealed substantial variability across studies (Q = 119.497, P < 0.0001; I² = 92.47%), suggesting true differences beyond chance with the random-effects model showed a stronger association compared to the fixed-effects model (OR 2.979 vs. OR 1.929). Sensitivity analysis demonstrated variations based on sample size. Publication bias of the included studies was done using Egger’s and Begg’s tests. Conclusion: The analysis revealed the effect of fast food consumption on weight status varied among demographic subpopulations. The review also provides further justification for interventions to encourage healthier dietary choices and reductions in consumption of fast food, both of which, in turn, are aimed at tackling the obesity epidemic. https://ijph.tums.ac.ir/index.php/ijph/article/view/37530 https://ijph.tums.ac.ir/index.php/ijph/article/download/37530/8639