How Many Calories in a Diet A&W? The Zero-Calorie Answer
                                
                                
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                                    4 min read                                
                            
                                A 12-ounce can of Diet A&W Root Beer contains exactly 0 calories, and the same holds true for A&W Zero Sugar, which is the re-branded version of the classic diet drink. This calorie-free status is achieved by using artificial sweeteners to deliver the signature sweet taste.