Cola-type soft drinks can damage your kidneys. FACT. Despite their global popularity, there's nothing remotely healthy about cola beverages: Drinking 16 ounces or more daily (whether diet or regular) doubles your risk of chronic kidney disease, according to a recent NIH study of more than 900 people. The researchers already knew that consuming any type of soft drinkthe average American adult guzzles 59 gallons' worth per yearis associated with several risk factors for kidney disease (hypertension, diabetes, and kidney stones), but the spike in the cola category was remarkable. Experts suspect that the ingredient phosphoric acid may be the culprit; it's been repeatedly linked to "urinary changes that promote kidney stones," say the study authors. Cola has an additional knock against it: Consumption is associated with significantly lower bone density in women, increasing the risk of osteoporosis and bone fractures, says a separate study. Bottom line: If you're going to indulge in an occasional soda, go for Sprite, 7-Up, ginger ale, and the likethe NIH study found that noncola drinks didn't have the same impact on the kidneys. But you'll be better off if you skip soda altogether, even the sugar-free varieties: Recent research showed an association between drinking diet soda and weight gain.