Diet Coke was my go-to drink - as mentioned above, I would pound down 2-3 liters a day, easily. It was a "safe" choice when I started the weight-loss trail. I found, though, that I was craving more sugary snacks, and when I would try to compensate for those added calories by skipping "real" food, the caffeine would kick in with a vengeance. Hands shaking, heart pounding - sometimes kinda scary...So, I made the decision to give up the DC habit, and went to green tea. Straight water - doesn't incite any real desire to chug - meh.
Best choice, by far, for me. I make my own, sweetened with stevia, and flavored with mint (fresh in season, extract in winter) and lime juice. Easy to get enough fluids (drinking 3-4 quarts per day), refreshing, and no shakes. Much lower in caffeine than the coke. And fewer cravings. I did experience the "whoosh" when the changeover occurred - a quick 5 lbs...but beyond that, I didn't find any major changes in weight loss speed.
