What Happens!
I drink three cups of regular coffee each morning. My surgeon would rather that I not do that but did say if I just have to, I can have one cup. I have to have three. But pre-op, I drank a whole pot by myself every morning so three cups is much better. Caffiene deplets your bone calcuim and this is a problem that will not show up on your labs. It will say calcuim is normal. All that will catch it is a bone denisity test. Also, caffiene is an appetite stimulant which we do not need. So, even tho I do drink coffee (regular) it is much better not to. There are also other reasons it is bad for you but I forgot. Oh, it is also a pouch irritant and can cause ulcers .
I was drinking decaf for awhile post op but ran out and drank caffienated. It didn't have an effect on me that I can see right now. I know they don't recommend it, but I try to limit it to 2 cups of coffee. I also have diet sodas occassionally that are not caffiene free. Again, I don't feel any effects, but I'm sure there are some.