There are some people who do liquids before, so she isn't completely alone! My recommendation would be that you get some good soups. For me, broth was nasty and far too salty. I went to a soup shop and strained soups. I drank the liquid, and my dogs ate the pieces. They were very happy during my two week post-op liquid stage!

In this case, you can have the rest of the soup.
She can also probably have sugar free popsicles. They aren't nearly as bad as the broth, but they are hard to come by. My Super Wal-Mart had one brand that came in sugar free.(Those are EXCELLENT to have after surgery.) Since this is pre-op, she can probably have the regular, but she might want to go ahead and get in the habit of cutting down on carbs.