from what i read before, cool water also can be one of the slimming trick.
try to think about it, when you drink the cool water, your body will eventually need to warm it down to the correct temperature, which mean your body will use ENERGY to warm it down, so your body will burn more energy. This is just the theory that i read from other people's little trick. For me, it do make sense but how good it is, what is the side effect of it (coughing, etc) i dont know.