The prevalence of overweight and obesity in China is increasing rapidly, making it a pressing issue for academic investigation. This study seeks to assess how marriage influences overweight and obesity among the Chinese population. Data were drawn from the China Family Panel Studies (CFPS), a comprehensive national longitudinal social survey. A total of 44,095 individuals were included in the analysis, utilizing four waves of panel data. Fixed effects regression analysis was employed. Overweight and obesity were classified using BMI thresholds of ≥ 24 kg/m² and ≥ 28 kg/m², respectively. Findings indicate that marriage is associated with a notable rise in the likelihood of being overweight by 6.5% (p < 0.01) and obese by 2.8% (p < 0.01). A key contributing factor appears to be a decline in exercise habits following marriage, as marriage leads to reduced physical activity while having no statistically significant impact on alcohol consumption. The effect is particularly pronounced among individuals aged 20–30, whereas no significant association is observed for those between 40 and 50 years old. Marriage emerges as a significant socioeconomic determinant contributing to overweight and obesity. There is an urgent need to promote weight management among married individuals, and public health authorities should prioritize improving access to exercise facilities to support this goal.
