Europe Says Diet Coke Is Safe
Aspartame is "safe for human consumption," the European Food Safety Authority said yesterday.

“This opinion represents one of the most comprehensive risk assessments of aspartame ever undertaken,” said Dr. Alicja Mortensen of the European Food Safety Authority, an independent agency funded by the E.U., yesterday. That opinion: "Aspartame is not a safety concern."
Safe doesn't mean perfect; it just means safe. They concluded that we do not have grounds to believe that the artificial sweetener causes cancer or affects behavior or cognitive function, in children or adults—in quantities up to 40 milligrams per kilogram, which, for the average person, is the equivalent of around 17 cans of Diet Coke per day.
Conspiracy theories about aspartame still have massive audiences, credible detractors predictably trace links to food and chemical industries in every corner of the earth, and the acids in soda still erode your teeth; but the opinions of professional organizations have steadily accumulated in attestation to aspartame's safety since its 1974 FDA approval.
I think it is healthy to be innately skeptical of anything that's 200 times sweeter than sugar, including people who claim to be. At some point in this discussion, though, it's probably best to choose a side and live on it with resolute confidence. Drinking with guilt and regret is no way to go about things.