Obesity and the experienced cultural, economic, and climate variations among immigrants to high-income countries: An umbrella review of the literature

Abstract Objective: Obesity is a growing global public-health concern, particularly among immigrants to high-income countries. This umbrella literature review synthesizes evidence from systematic reviews to explore the multifactorial cultural, socioeconomic and environmental determinants of obesity and weight gain among immigrants to high-income countries. Design: A systematic search of PubMed, Web of Science, and Scopus was conducted from January 2015 to November 2025 to identify systematic reviews and meta-analyses examining the impact of cultural, socioeconomic, and environmental factors on obesity among adult immigrants (i.e., economic, students, and refugees) to high-income countries. Setting: 33 reviews were included and thematically synthesized under four domains: physical climate and physiological changes, socioeconomic stressors and psychological mediators, cultural factors, and methodological quality – rated using the AMSTAR tool. Results: The review found consistent evidence linking longer duration of residence and higher levels of acculturation with increased obesity risk. Socioeconomic disadvantage, food insecurity, and psychological stress—particularly acculturation stress—were key mediators of weight gain. Less sunny colder climates impacted on weight gain indirectly through limiting physical activity and accessibility to traditional-healthy diet outlets. Cultural dietary transitions and intergenerational differences further influenced obesity trajectories. Methodological quality varied, with only six reviews providing meta-analysis pooled estimates of obesity and being rated as high to moderate quality. Conclusions: Obesity among immigrants is shaped by intersecting cultural, socioeconomic, environmental and physiological factors. Public-health strategies must adopt culturally sensitive approaches that address structural barriers and support healthy transitions post-migration. Future research should emphasise longitudinal, intersectional, and climate-tailored studies to inform targeted interventions.