My surgeon didn't require a liquid diet. But I did have to lose a minimum 5% of my weight using South Beach diet. I had to lose 17 lbs (5%), but I lost 25lbs before surgery, also had to meet with my NUT a few times, keep a food diary, all before I could meet with my surgeon to schedule surgery, but of course they stagger the appointments so you can fit in all the tests, psych eval, blood work, etc. I had to have liquids the day before surgery and nothing after midnight.
Good luck to you!! Congrats on your 26 lb loss!!