RecruitingPhase 4ProcedureFibrosis Lessens After Metabolic SurgeryMetabolic dysfunction-associated steatotic liver disease (MASLD), formerly known as non-alcoholic fatty liver disease (NAFLD), a major global public health concern, is commonly associated with obesity, diabetes, and dyslipidemia. MASLD is currently the most common cause of chronic liver disease affecting about 80% of people with obesity, ranging from simple fat deposits in the liver to Metabolic Dysfunction-Associated Steatohepatitis (MASH), cellular injury, advanced fibrosis, cirrhosis, or hepatocellular carcinoma. Patients with MASH are also at risk for cardiovascular disease and mortality. There is no universally approved medication for MASH. Weight loss remains the cornerstone of MASH treatment. Patients meeting the inclusion and exclusion criteria and who give informed consent will be enrolled in the trial and undergo the baseline liver biopsy (if none available). Approximately 120 patients with MASH and liver fibrosis (F1-F4 in baseline liver biopsy) will be randomized in a 1:1 ratio to metabolic surgery or medical treatment (incretin-based therapies ± other medical therapies for MASH) and followed for 2 years at which time a repeat liver biopsy will be performed for the assessment of the primary end point.