Red Bull sugar-free is a carbonated beverage that energizes the body and mind without sugar and contains only 5 calories every 8.4-fl oz can. When to drink: Red Bull is one of the greatest energy drinks to keep on hand, and it is enjoyed by elite athletes, busy professionals, college students, and long-distance travelers all over the world. For individuals who need to stay focused during intensive meetings or creative brainstorming sessions, in action with teammates or competitors, or simply want to get the most out of life, a chilled can of Red Bull sugar free provides wings without sugar. What's in the can: Ancient civilizations drank caffeine from natural sources and were well aware of its energizing properties.