Coca Cola is not healthy for you and that should be the end of the conversation.
In binary land, maybe.
In real world, we can contine to ask: how is it unhealthy? As a diet coke addict myself, I went around and around in this issue, looked up studies, all different FDA-liker organization infos, and what I came up with is this:
- aspartame is safe to consume in the levels it is found in in diet coke, unless you have an allergy to phenylalanin
- it has no bearing on your blood sugar levels (that study relates to saccharine)
- the main coloring agent is E150, also known as caramel completely harmless (and if there were TONS of it in the diet coke, that 0g sugar would not stay at 0g
- it is NOT good to consume it without caring for teeth: do not just drink soda, it helps to balance it with non-soda water consumption
- citric acid indeed is an enemy of the enamel, so either use a straw or do regular checkups and minimalize the amount of damage it can do to your teeth (and remember to leave at least 40 mins between consuming soda and washing teeth, but feel free to wash off soda with regular water)
- It has caffeine in it, ~1l of coke amounts to roughly 1 medium coffee. So take that in mind.
Aaand that is it. Caffeine is good for you in normal doses. Its acidity is not good for you. If soda makes you bloated, do not drink it, obviously. But it is not killing you with all its power.