Help!!!
What's permissible under your surgeon's requirements is probably a question better suited to your dietitian. You see, some surgeons just want you to lose weight, and some emphasize low-carb in their pre-op diets. So it really depends on what your surgeon wants you to do.
That said, it's probably a good idea to go for whatever's going to give you maximum protein with minimum calories. The clear winner in that case is Zero Carb Isopure (40g protein for 160 calories), but you might want to try just a bottle before buying a large amount, because you might not like it. Another good choice is Nectar, which most folks seem to like. Good luck!
Those are all ok. But to start with you might want to try something that is not creamy or with milk because it will feel real heavy in your pouch. The fuzzy navel nectar is a good one you mix it with water.
I love Unjury to me it is the best tasting by far. They also make an unflavored one that is great mixed with Crystal Light. I like it mixed with the CL lemonade. You can order samples at www.unjury.com to try it ans see if you like it. The flavored ones are better mixed with ff milk though. I don't like them mixed with water.
I go to the WalMart in their vitamins and minerals section of the pharmacy and buy whey protien. Very inexpensive and good for you. They have it in chocolate, vanilla, and strawberry flavors. You can get a huge jug full for only about $15.00. For me to go and buy things like slim fast shakes and what not was way to expensive. This helped me quite a bit.