The present invention is a non-caloric or reduced calorie frozen carbonated beverage and a method of making it. The freezing point of a diet beverage syrup is reduced through the use of a freezing point depressant, particularly a Sugar MNS which is used to replace a portion of the known high-potency non-caloric sweetener. The preferred Sugar MNS for use in the beverage and method of the present invention is erythritol.