Bariatric Surgery Versus Non-alcoholic Steato-hepatitis

This is a Randomized Controlled multicentre Trial involving the Catholic University (Professor Geltrude Mingrone as PI and Professor Marco Raffaelli as co-PI) The research question in PICOT format (P) - Population: Adults 25 to 70 years of age and BMI ≥ 30 and ≤55 kg/m2 with histological diagnosis of NASH. (I) - Intervention: Roux-en-Y Gastric Bypass or Sleeve Gastrectomy, both plus lifestyle counseling. (C) - Comparison: Intensive Lifestyle Modifications. (O) - Outcome: the histological resolution of NASH without worsening of fibrosis at 1 year after the interventions. (T) - Time: One year after the intervention started. 1.3.3.2 Research Goals * The primary aim of our study is to assess the effects of bariatric-metabolic surgery or ILM on NASH at 1 year after the interventions. * Secondary aims are to assess the safety of bariatric surgery and the improvement of at least 1 stage of liver fibrosis without worsening of NASH, insulin sensitivity , T2DM, and lipoprotein profile changes. The liver biopsy will be performed at baseline and at 1 year follow-up. Another liver biopsy will be performed at 3 and 5 years follow-up.