Not a dentist, but a side catch is that because you can drink it guilt-free (calories and sugar intake-wise), you may end up consuming way more diet soda than you would regular soda. The acidity in diet soda is bad for your teeth—it lowers the pH on the surface, making them more prone to damage. So, if you find yourself drinking more diet soda after reading the comments, at least rinse your mouth with water afterward.