After having gastric byp surgery, why are you not supposed to drink sodas?

i had gastric byp surgery about 3 years ago. although i'm really not supposed to, i drink sodas now all the time (diet of course b/c of the sugar thing) but i didnt dare touch a soda for about the first 8 or 9 months after surgery. the main reason is the carbonation. it swells your stomach up causing it to expand, and over time can lead to permanent expansion, and then as time goes on you run the risk of being in the same boat as you were before the surgery. your stomach swells - over time permanently swells- and you can eat just as much as you could before causing weight gain again. i'm just really carefull with it now....hope this answers your question!