God save us, Granny says someone drank ten litres of Coke a day. Ten litres! And now they are dead, at 30. Condolences to the family.
The are reported as saying they didn't know Coke is bad for you; it's a soft drink. In case either of my readers, or any stray visitors or lost people browsing about is unclear about the fact:
Coke Is Bad For You. Soft Drinks Are Bad For You.
To be fair, in moderation soft drinks are unlikely to have any major effects, and they go well with various alcoholic beverages, however, I digress.
Soft drinks are full of sugar, and sugar is addictive.
Coke is full of caffeine (though it is not the worst offender - Red Bull, anyone), and caffeine is addictive.
Caffeine and sugar - very addictive.
The article referenced quotes a doctor as saying a severe potassium deficiency may have contributed to the death, and such deficiency can be caused by the excessive consumption of soft drinks. If I were part of the family I'd quit the "we didn't know" line and start talking about Coke's addictive chemistry.
The Clash - London Calling, 1979