I have diet Pepsi all the time. Now someone tell me why I shouldn't...I know it's coming... :-
Theres actually chemicals in diet soda that allow you to retain more fat and water. Of course that will happen if you drink diet soda or any other form of soda in excess. http://www.mayoclinic.com/health/diet-soda/AN01732
What are these chemicals? I didn't see anything about it on your link.