yep, I've read that too. Even the aspartame itself can be converted to formaldehyde when it sits in a hot warehouse, before it ever enters our body!
What I still wonder is whether the aspartame or sucralose actually trigger an insulin response in the pancreas. There was a recent study that showed the brain responds to any sweetener, natural or artificial, by causing us to crave more. So, is that the reason that people in the diet soda studies had insulin problems, and because they didn't 'waste' calories on soda, so they ate more of other things that did provoke the pancreas, or was it the aspartame itself? I'm thinking the acidic environment that any carbonated drink causes is also the problem. It would be interesting to see somebody study carbonated drinks with stevia, which is supposed to help control blood sugar.
At any rate, soda is bad...any kind. Tasty, but bad for us.