Well, aspartame isn't supposed to be good for you, and neither is splenda (which one do they use in diet coke? I donno). And 8 cans, well, that's a little excessive. No, a lot excessive. I probably am drinking healthier when I have 2 or 3 cokes a day.
Learn about Aspartame if you insist on ingesting so much of it..
Aspartame Kills