I used to drink coca cola light (I think it is the same you can diet coke in america) a LOT!
I went cold turkey 1 year ago and drank sugar drinks instead and 8 months ago I gave up on soda-pops alltogether. All brands and types.
My reason for doing so wasn't that it is poisonous or something. It obviously isn't or we wouldn't be talking about it. Everything in excess though is potentially harmful to a certain degree. To see this scientifically, what can be harmful about drinking diet coke instead of water:
1st Sweeteners. The body is not a foolish bio-machine. It KNOWS when you cheat it with sweet taste and no calories. So it makes you crave for more. Sweeteners are mildly addictive (it depends on the "user's" temperament also) and offer you nothing except their taste. There has been no serious long term study to see the long lasting effects of sweeteners in a diet. We probably are going to be the living study 30 years from now... I'd rather watch from afar thank you.
2nd Acidity. The acidity of carbonated drinks is usually high. They endanger the health of your teeth, cause and worsen ulcers and change your whole digestive track's ballance. So compared to neutral water you are doing damage.
3rd Phosphorus. Cola drinks have lots. Phosphorus is essential but should be consumed at about the same doses with calcium and vitamin D. Or else you might get calcium defficiency (osteoporosis for us ladies is a serious business).
4th economy. You can actually save LOTS of money by drinking tap water instead of soda. You could be surpised how much money goes into that need. Buy a water filter for your tap and you will see your budget rising.
5th Aftertaste. Sodas leave a bittersweet aftertaste if they have sweeteners, which conveniently only goes away if you drink more of the stuff. Once you stop drinking you'll feel the taste of other foods much stronger.
6th Bloating. Sodas cause bloating... not much to say on this
7th Cellulose. It has been suggested in some studies that carbonated drinks cause more cellulose...
8th Hunger. Carbonated drinks cause hunger, because they lessen the feeling of fullness (through burping, like cooking soda does). So you feel less full faster after a meal if you drink carbonated stuff with it, or after it.
In the end if you HAVE to drink it to feel happy try a can every other day. I think the list above might help
