Researchers gave college students vodka drinks with regular soda and with diet soda, and the diet soda group got more intoxicated, faster - about 20% more intoxicated than those who mixed regular soda with liquor, according to research published Tuesday in the journal Alcoholism: Clinical & Experimental Research. Sugar in your mixed drink actually slows down the effects of alcohol, researchers say.
Though it was a very small study, only eight women and eight men, the findings closely match previous research linking diet drinks and increased alcohol levels in the body.
I know diet soda seems a bit more carbonated than regular soda to me as well. I wonder if that is a factor?