My pre-op diet was one of the less restrictive ones. It was shake for Breakfast, mid morning high Protein snack, shake for lunch, afternoon high protein snack, dinner is 4-6oz lean protein, veggie and small carb if you want it, if still hungry another Protein Shake for after dinner snack (I generally skipped this). High protein Snacks included hard boiled egg, Jerky, lunch meat, string cheese, 2-3oz lean protein, greek yogurt etc. Basically at least 10g protein and less than 200 calories. It worked out to around 1000-1200 calories per day, 80-100g protein and less than 100g carbs. Definitely less restrictive than all liquids but I still lost around 10-12lbs I think and it was livable. Something like that may be easier to stick to since it's not enforced by your program.