Could the removal of the gall bladder have any link to weight gain?

My mother got her gall bladder removed several months ago and is flustered because she has gained about 15 pounds since then. I told her I would look into the matter. I have done a little research and found that some affects after the removal of the gall bladder are loss of appetite and vomiting. Now, I would like to know if the opposite could also be true, or perhaps slowed metabolism or something similar.