Quick question. As a triathlete, the people in my office are always turning to me for training advice. I'm helping a couple with their workout goals and such, and both say they want to lose weight. However, they both claim that drinking "diet" sodas can't hurt them in this goal because there are no calories, no sugar, etc etc. I contend they are wrong, because even though they are diet, it still gives your metabolism the "spike" which then creates a valley, which you don't want.
Does anyone have any evidence to back me up? I know I'm right, I just can't prove it. I want them to drink water or tea or even coffee to get their caffeine fix, but they both still like their diet sodas...
Thanks for the help.