Cholestyramine
"I too had my gallbladder out 15 years ago and immediately following removal gained 30lbs in three months and had constant loose bowels (dumping syndrome). My doctor had told me the weight gain was because I was now able to eat.  His comment annoyed me. It just wasn't true. I knew it had to be something more than that. I had never been over weight before and my digestion just seemed so out of wack.   I stayed away from the doctor and tried my own things. Diet, exercise...nothing worked. 10 years later I went to a new woman Dr. and she prescribed Cholestyramine.  It works great. I take it 1 x per day. What I do notice however, is it must be taken with a lot of water or I will get heartburn.  If I skip a dose my problem returns immediately."