Water should be drunk at room temperature, as it is less of a shock to your system but I've heard that Yes, if you drink 1 liter of ice cold water you will lose 20 calories. Drink a glass of warm water also before meal, because it fills our stomach quickly so we avoid of eating too much. I used to drink a lot of warm water all day long. I don't like cold drink and ice. I believe warm water disabsorbed fat.