Probably the crappiest of all pre-surgery diets. Three 20 ounce servings of skim milk or milk alternative (Fairlife), 1 serving of low sodium broth, and at least 50 ounces of water (flavored drinks of low/no calorie under 10 only) per day. I am a wateraholic, so I down 120 ounces a day, minimum, so that part isn't hard. Depending on BMI, the clinic has patients do it for 2-3 weeks.
Fortunately, I only have to do 2 weeks, but I did 1 week in March. At about 550 liquid calories per day and 160-170 ounces of fluids, I got dizzy and peed A LOT, but I dropped a pound a day. One of the best ways to get through it was blending with ice to thicken and adding sugar-free syrups to change up the flavor each time. The sweetness made me crave savory though. I'd pump up my evening "dinner broth" with paprika, a few drops of Cholula, or add some peppercorns as I heated it. And sometimes I'd freeze a portion of my daily 60 ounces in these mini silicone popsicle molds to make something I could nibble on.