you're not finding it on Google because all surgeons have different requirements. I was allowed to have 4-5 shakes a day, plus all the ultra-low or no-calorie fluids I wanted (Crystal Light, water, etc). No food or higher-calorie beverages. Some people are allowed to have one small meal a day. Some people are on the pre-op diet for a week, some two, some three, some aren't required to do a pre-op diet at all.
I'd ask your clinic that question since it's their requirement...