The Pseudoscience Behind So-Called Energy Beverages

I welcome your comments, either for or against, the seeming science or pseudoscience behind a generation of so-called energy drinks. I contend that if the product claims zero calories, then the product contains zero energy. I think the confusion is between a true measure of energy, such as the energy to run several miles or to drive a car to a distant location, and central nervous system stimulation. Some clarification is in order. Comments please.