Effects of Functional Oils on Obesity With Mild Cognitive Impairment

Inclusion Criteria: * Meets the diagnostic criteria for obesity combined with mild cognitive impairment (MCI) (obesity: BMI ≥28.0 kg/m\^2 per the 2022 Chinese Expert Consensus on Obesity Prevention and Treatment; MCI: Montreal Cognitive Assessment \[MoCA\] score below the education-adjusted cutoff, confirmed by a neurologist) * Aged 45 to 75 years * Has not been on a diet or has discontinued dieting for at least 3 months, and has not taken fish oil or similar supplements, or is willing to discontinue such supplements for 3 months prior to the intervention * Able to accept and consume DAG oil as part of daily diet * Voluntarily agrees to participate and signs the informed consent form Exclusion Criteria: * History of neuropsychiatric disorders such as stroke, epilepsy, or schizophrenia * Cognitive impairment attributable to depression, thyroid disease, traumatic brain injury, or drug- or alcohol-induced intoxication * History of cerebrovascular disease, or cognitive decline due to severe impairment of cardiac, hepatic, pulmonary, or renal function * Use of antibiotics, health products, or nutritional supplements within 2 weeks prior to fecal sample collection; or gastrointestinal symptoms (trauma, inflammation/infection, abdominal pain, diarrhea, or constipation) or vaccination history within the same period