Effects of Berberine in Reducing Abdominal Visceral Adipose Tissue Among Individuals with Obesity and NAFLD

Inclusion Criteria: * Participants aged ≥18 years * Participants with obesity (i.e., BMI ≥ 28 kg/m2) and abdominal obesity (i.e., waist circumference ≥85 cm in female or waist circumference ≥90 cm in male) * Participants with NAFLD diagnosed by ultrasound, computed tomography or magnetic resonance imaging Exclusion Criteria: * Patients with established coronary heart disease, stroke, or peripheral arterial disease * Patients diagnosed with diabetes or taking oral glucose-lowering drugs * Patients with severely uncontrolled hypertension (i.e., SBP≥180mmHg and/or DBP ≥110mmHg) * Excess alcohol consumption (i.e., alcohol ≥ 20 g/day in female or alcohol ≥ 30 g/day in male) * Other causes of fatty liver disease, including alcohol or drug abuse, hepatitis B or C, autoimmune, hepatolenticular degeneration, total parenteral nutrition, inflammatory bowel disease, celiac disease, hypothyroidism, Cushing syndrome, β -lipoprotein deficiency, lipid atrophy diabetes, Mauriac syndrome, etc. * Patients with thyroid disease, including hyperthyroidism or hypothyroidism * Patients with cardiac insufficiency * ALT or AST ≥ 3 times upper limit of normal, liver cirrhosis or hepatic insufficiency * Patients with renal insufficiency: estimated glomerular filtration rate (eGFR) \< 60 ml/(min×1.73m2) * Patients who had weight loss surgery, or are currently taking drugs for weight loss, or plan to have weight loss surgery or drugs in the following 6 months * Patients diagnosed with glucose-6-phosphate dehydrogenase (G6PD) deficiency * Taking berberine or drug containing berberine in the past 1 month * Any adverse reaction to berberine * Severe constipation, diarrhea, and/or severe chronic intestinal diseases (e.g., ulcerative colitis, Crohn's disease, irritable bowel syndrome, etc.) * Patients who had to use long-term or intermittent corticosteroids, immunosuppressants, antibiotics, or other drugs that affect inflammatory biomarkers * Women who are pregnant or breastfeeding, or those who plan to be pregnant during the trial * Patients with malignant tumors * Patients with mental disorders, cognitive disorders, and/or other serious diseases * Those who participated or have been participating other trials during the last 3 months * Any other conditions that may hinder the compliance to the study intervention or follow-up visit