Protein!!! Protein!!! Protein!!!
i use Now Sports unflavored whey protein isolate. I buy it by the 10# bag, and flavor it with different extracts, dark coaco powder, cold decaf hazelnut coffee and sweeten with splenda. Regular sugar gives me gas from hell and dhr. Make sure you get a couple Blender Bottles, if you don't have them already. That little wire ball will get the lumps out of anything!
BTW...if you're having a lot of gas and dhr, you could be lactose intolerant. A lot of DSer's are right after surgery, even if they weren't before surgery. That's the reason I use whey protein isolate, because most of the lactose is processed out of it. If you weren't LI before surgery, and you are post-op,it will probably go away after your new anatomy matures a bit. If you were LI going in, you will be worse post-op. That little nugget was from my surgeon, after straight whey protein dehydrated me to the point I had to go back in for fluids. If you use milk, use whole milk and add some heavy cream. Lowfat (2%) and skim contain more lactose. The lower the fat content in milk, the higher the sugar (lactose) content.
Never, ever let go of your shakes completely! If you find you can eat 120g of protein daily, go for it, but I have to supplement with shakes. One of my compatriots had a nasty bout of protein calorie malnutrition after trying to eat all her protein.