A study examined the link between body mass index (BMI) and activities of daily living (ADL) disability in older Chinese adults using data from the China Health and Retirement Longitudinal Study between 2011 and 2020. The analysis included 3,975 participants and tracked their BMI and ADL disability over a median follow-up of seven years. Results showed that 2,003 individuals developed ADL disability. The research found a significant correlation between BMI and the risk of ADL disability, with obese older adults facing a notably higher risk than those with normal weight. A U-shaped relationship was identified, indicating that both low and high BMI levels increased the risk of ADL disability, particularly in adults aged 60-69 and older women. Despite some limitations, including the observational nature of the study and potential confounding factors, the findings underscore the need for regular BMI assessments and targeted weight management to prevent or delay ADL disability among older adults.