I have found that after being sleeved and not having any diet coke for nearly a year, I just don't like the taste anymore and definitely don't like the carbonation - it make me feel too full, even small sips. Never have liked a "flat" soda. So for me it's a no brainer - I just don't drink them. My medical team said not to, so I don't. I trust them, they are experts.
As for fried food, I may have a little on occasion and I do fine with it. Anything that is very greasy I avoid altogether. I was never a big fried food eater to begin with.