Every doctor has his/her own protocols. When you see your surgeon, you can ask about the liver reduction diet (liquid diet everyone is talking about).
My surgeon requires it, and since I've held my weight steady this past month, I need to do the two week liquid diet. If I had lost more weight, then it would only have been for a week.
Mine is 4 shakes/day and a large garden salad with a drizzle of extra virgin olive oil for either lunch or dinner. In between, drink water, Crystal Light, SF Popsicles, SF Jello, zero calorie drinks, like Vitamin Water Zero, etc.