Ok so you crave a pre-op luxury. Sounds like your a human being to me! You know that having a fizzy drink might stop your surgery working & I'm sure your not silly enough to risk this , so go & get yourself a cola flavoured ice lolly, a chewy cola sweet (just 1 though- they're not good 4 u!) or a sugar free lolly.
If I want chocolate (my full fat coke!), I'll have an options hot choc. It's not the same but its good enough & it gets me through. It's no longer a compromise but a welcome choice.
You're a grown woman, you can make a good choice. You know full fat coke it a no no, even if you still want it! A lot of people on here have said that their tastes change post surgery, maybe it wont be as good as you remember? You know you shouldn't do it, make a positive change now. If I had the choice of full fat coke or chocolate v early death from obesity, i know what I'd choose!