The purpose of this study is to investigate the effects of diacylglycerol (DAG) oil on obesity accompanied by mild cognitive impairment (MCI). Participants aged 45 to 75 years with obesity and MCI will be randomly assigned to two groups: a control group receiving regular rapeseed oil (RSO) and an experimental group receiving rapeseed-based DAG oil. The dietary intervention will last for 6 months. The main goal is to observe whether this functional oil intervention can improve cognitive function and regulate white adipose tissue browning.