That's news to me. Wikipedia also notes that Aspartame which is the sweetener used in most diet soda, has not been found to be carcinogenic with a bunch of citations.

Or are you talking about other ingredients?

He's not. Artificial sweeteners are one of the most demonized additives on the planet despite being one of the most studied. Because people are so often looking for a reason to get rid of them.

Even the studies of them being bad for "getting used to sweetness" and thus making people more obese through compensatory over-eating are studies that rely on self-reporting and polling.

When properly controlled, physics works as it always has and you can't magic mass or energy out of thin air.

If you're talking about aspartame it's about as possibly carcinogenic as the moon landing was possibly faked.