Yikes, right? Researchers made this discovery after measuring the drinks’ phosphorus content in a lab, then comparing their numbers with the drinks’ phosphorus content in a food database used by health professionals. In some cases, phosphorus content among the same brand varied by as much as 260 mg per cup. [block:bean=sub-offer-flatbelly-flexblock] The bigger problem: Many packaged foods, not just drinks, contain phosphorous additives, yet the FDA doesn’t require companies to list how much on the label. In fact, a 2013 study in the Journal of Renal Nutrition found that 44% of the best-selling grocery items contained phosphorus additives—some food categories that topped the list were frozen meals, dry food mixes, breads, and soups.  MORE: 7 Daily Habits That Are Totally Sapping Your Energy To limit your intake of unnatural sources of phosphorus, says Alexander Chang, PhD, study coauthor, skip drinks—or any food in a package—with ingredients containing the prefix “phos-” such as phosphoric acid, commonly used in sodas to give them their signature sharp flavor and to act as a preservative. (Get a Free Trial of Prevention + 12 Free Gifts) The good news: If you stick to mostly fresh, whole foods and drink water or a naturally flavored seltzer like Hint Fizz, you’ll be just fine.