Manufacturers of energy drinks may want you to think the “energy” is coming from special blends of herbs and other substances, but their key ingredient is almost always caffeine—often a hefty dose that’s not disclosed on labels. Moreover, the drinks supply “energy” by providing calories, specifically from sugar. (These beverages shouldn’t be confused with sports drinks, such as Gatorade, which are designed for endurance exercise and are relatively low in sugar and have no stimulants.)
How much sugar is in energy drinks? Often a disturbingly high amount, according to an analysis of 197 products by the U.K.-based Action on Sugar—with one having 78 grams (nearly 20 teaspoons) in a 17-ounce (half liter) can, which is more than triple the daily limit recommended by the American Heart Association for most women and teens, and about twice the limit for most men. Half the drinks had at least as much sugar, ounce for ounce, as soda. “These products serve no purpose whatsoever but make children addicted to caffeine and habituated to sugars,” according to Action on Sugar.
Don’t think that only the U.K. serves up super-sweet energy drinks. Products sold in the U.S. are often just as bad, including Rockstar, which has 62 grams of sugar (nearly 16 teaspoons), Amp with 58 grams, and Monster Energy with 54 grams per 16-ounce can. Many of these drinks now come in artificially sweetened versions, but that doesn’t make them risk-free.
Many energy drinks are a witch’s brew of stimulants and other compounds that can have potentially adverse effects on the cardiovascular system. This was seen in a Mayo Clinic study in the Journal of the American Medical Association, which involved 25 healthy young adults who drank a 16-ounce can of energy drink (Rockstar). Testing 30 minutes later found a 6-point rise in blood pressure, along with a dramatic boost in norepinephrine (a stress-related neurotransmitter). That’s not surprising, since the can contained 240 milligrams of caffeine (as much as in two or three cups of coffee), plus guarana (also a stimulant), along with taurine, milk thistle, and ginseng. This was just a small study using one particular product, but it’s likely that similar drinks would have comparable effects.
Bottom line: With all that sugar, many energy drinks are like liquid candy. Worse still, their high caffeine content can be harmful for people sensitive to this stimulant, those with certain cardiac conditions, and children and teens (especially when combined with alcohol, a common practice). In fact, about two dozen deaths have been linked to high-caffeine energy drinks, along with hundreds of other adverse events, including seizures and cardiac arrest. For more information, see Caffeine in Energy Drinks.
Also see Is Sugar Making Us Sick?