It's important to review this with your chosen Operating Surgeon. A proper nutrition pre and post surgery is essential.
Thank you for sharing your excellent question. Depending on the exact composition of your liquid diet I would not advocate any change to your nutrition that may compromise your healing. If your diet is intended to lose weigh rapidly in anticipation of your surgery you will likely be nutritionally deficient and your body will not have the building blocks to be able to appropriately healing the incision. Talk to your surgeon.