It's worth noting that diabetics often do this almost as a matter of course. If diet soda were spiking diabetic people's insulin, they would almost certainly know.

Some of the most avoid consumers of diet soda I've known are diabetics who checked their blood sugar multiple times a day at least.

Avid|Avoid makes for a pretty big difference here :-)

Avid is what I meant. My cell phone keyboard apparently disagreed. ;)