Does Coca-Cola Convert rust? Results

What I want to know is why phosphoric acid is in Coca-cola in the first place... makes sense every once in a while I drink a coke my teeth feel like they're dissolving (because they basically are)
I think the sugar is even worse. Do you know how sunlight cross-links plastic, making it yellow and brittle? Sugar acts similarly in your body, aging it. A can of Coke contains about 11 teaspoonsfull of sugar. I drank lots of it before I got diabetes, now I don't.