i drink a ton of water, but i have found that i can have a diet coke every now and then and not upset my diet. It is just important to not make soda your only form of hydration, or even a majority of it. i think the only reason people say no soda, is because the know people drink like 8 in a day. that is not a good way to lose weight. having 8 bowls of total in a day would not be a good way to lose weight. my point is that it is hard for many people to be moderate in their eating and drinking habits. therefore people tell others that they cannot have any this, or that. it is just simpler than trusting them to bigest rule in health - do not eat or drink anything in excess. easier said than done, but it is that simple (with excersize)