I had surgery on Nov 17th and have been dealing with this as well. I did fine for the first two weeks of liquid post op and first 2 weeks of purees. Then the excessing loose bm started. At the suggestion of my surgeon and dietitian I went back to clear liquid for 24 hours and it stopped. So the general feeling it's food related. Now I'm adding things in slowly and figuring what foods are triggering it. So far artificial sweeteners and certain proteins have triggered it. I'm only in my second week of reintroducing things and I'm hopeful it will continue to improve!