I'm pretty sure you already know that three lites of soft drink, sugar free or not, in one day probably isn't that great for your system. Pepsi Max contains aspartame, as does Coke Zero, and this is one of the most contraversial artifical sweeteners I have read about. At 3L per day, that's over 20 litres a week and I know I wouldn't be comfortable ingesting that amount of artificial sweetener.... but that the end of the day, it's your body and your choice what you do with it.
"Eat well, your life depends on it"
Progress to first mini-goal, deadline: 30 December 2008!
To believe you can, is everything.