I read an article in The Guardian in May which really put me off coke/pepsi for life.
It was talking about the chemicals used to make these drinks and their so called healthier counterparts, diet coke and caffiene diet coke. The chemicals can damage your stomach lining, give you headaches, interupt your sleep, make your muscles ache and so on.
Me and OH always had a stash of caffiene free diet coke in the fridge (we are a caffiene free house). After that article we binned them all and bought a water fliter jug. The only real difference I have noticed after 7 months is that I do get much fewer headaches....but then that could be because I am drinking LOTS of water.
I know it can get annoying when the papers say 'this is bad, that is bad for you'. We wouldn't end up eating anything...but I am glad this is one change I did make.