Experts feel that increased findings of fatty liver disease in the american population corresponds to obesity and very highly fat and processed diets (in the face of normal weight). There is a strong possibility that significant weight loss will also help to reduce the fatty liver situation.  Remember that even though you will have a physical barrier to overeating after surgery, you need to work on lifestyle habits that support eating less and exercising more.  It's not just a magic operation and in fact, if you are not vigilant, you can undo the surgical intervention and stretch the new pouch over time.  make sure you ahve therapy and a support system in place before and after surgery.  Also be aware that you will need significant daily vitamin therapy.