there was water—abundant, refreshing, providing everything the body needs to replenish the fluids it loses. Humans relied on it as their only beverage for millions of years. Milk came next, with the advent of agriculture and the domestication of animals. Then beer and wine and coffee and tea, all drunk for taste and pleasure as much as for the fluids they provide. The newcomers—soft drinks, sports and energy drinks, and the like—offer hydration but with a hefty dose of unnecessary calories that the body may have a hard time regulating.