My pre op diet consisted of 3 serves of Optifast a day either in shake, bar or soup form. I was also told to make sure I get 1 teaspoon of oil per day to avoid gallbladder issues. I was then also given a list of approved vegetables which included, broccoli, celery, onions, tomatoes, carrots, asparagus, mushrooms, capsicum, cauliflower, lettuce, cabbage and brussel sprouts. (a few other things that I can't remember off hand). I used to stirfy them up using my teaspoon of oil. Or make a salad. I only had to do the totally liquid for the day before and of course after the surgery.
The purpose of this was to reduce the size of my liver and to make it softer so it could be easily moved out of the way during surgery.
As others have said in this thread, please go check with your nutritionist or surgeon to make sure you aren't missing out on key things because you still need nutrition and broths won't be enough.