In the long run, it can help with cutting back on needless calories because sometimes we eat when it's really more thirst than hunger driving us. Plus it is hard on you to get dehydrated; drinking a fair amount of water is just a good general health practice. Some things that cause water retention can't be helped. Water retention affects the size of the weight window - the "jitter" of scale readings that you get when your base weight really isn't changing. The size of the window varies from person to person. I worry more about moving the window down than I do about where I am in the window. That's easy for me to say because my weight window is usually only a couple of pounds.