J pouches expand over time, but part of that process involves resisting the urge to evacuate for a while to facilitate the expansion process. I am surprised your surgeon did not provide this instruction. I was told to take Metamucil daily and resist the urge to have a bowel movement, as long as possible, so the pouch expands to accommodate having a certain stool storage capacity. Eventually the pouch did expand and I settled into maybe 5-6 BMs per day.