Well what I had done, still requires those two as well.
I can tell you that Pre-Op I went on the Opti-fast diet by Nestle, I had a Shake for Breakfast, Bar for Lunch and I had the Desserts for Dinner (You still feel naughty having a Chocolate Pudding for Dinner for two weeks, After the First 3 days of cravings it went quite well and I lost 12 KGs on it.