three weeks post op I was drinking a half can of diet Sprite (ZERO) no problem at all, with two caveat: absolutely not with food, minimum 1 hr before or after food. Just tonight (4 weeks post op) my Coca Cola addiction got the best of me, I drank some while eating, and it was the first major mistake I've made since surgery. I was VERY, VERY, uncomfortable; bloated and in pain. I chased my 3 yr old around the house to hopefully aid in digestion, it worked, brought up a huge burp but a burp that contained the contents of my stomach. This of corse is a vomit-burp, or simply, a VURP.
If you want to have soda, sip it slowly and keep food out of the equation.