Hi
The pre-op diet is different for each person and each doctor. It depends on your weight, pre conditions, BMI, and the doctor's preference.
Dr. Ortiz's clinic gave me 3 options for a pre-op diet...all of which were designed to help patients lose 5 % of their weight before surgery. This is the one I chose:
Protein shake (for Breakfast and lunch) no more than 240 cals each
lean cuisine for dinner - no more than 350 cals
up to 4 lbs of greens (salad, yellow/red/orange peppers, cuke, mushrooms) per day and ultra low cal dressing.
I found the first 3 days hard as my stomach adjusted to the lower cals but after that it went well and I lost my 5% and lots of inches. I only had to follow it for 2 weeks but I did an extra 3 days (dieter's mentality...had to start on a Monday)