Red Bull is one of the most well-known brands of energy drinks out there. Image courtesy Amazon Energy drinks are supposed to do just what the name implies -- give you an extra burst of energy. As it turns out, most of that "energy" comes from two main ingredients: sugar and caffeine. A typical energy drink can contain up to 80 milligrams of caffeine (about the same amount as a cup of coffee). By comparison, a 2006 study found that the average 12-ounce soda contains 18 to 48 mg of caffeine. Other than caffeine levels, how do energy drinks differ from sodas and sports drinks? Soft drinks are mainly water, sugar and flavoring. They don't do anything for your body; they're just supposed to taste good. Sports drinks are designed to replenish fluids lost during activity. They typically contain water, electrolytes and sugar. Energy drinks have added caffeine and other ingredients that their manufacturers say increase stamina and "boost" performance. They're designed for students, … [Read more...] about How do energy drinks work?