Diet soda is doing these 7 awful things to your body By Mandy Oaklander, Prevention nbcnews.com Pop quiz! What's the single biggest source of calories for Americans? White bread? Big Macs? Actually, try soda. The average American drinks about two cans of the stuff every day. "But I drink diet soda," you say. "With no calories or sugar, it's the perfect alternative for weight watchers...Right?" Not so fast. Before you pop the top off the caramel-colored bubbly, know this: guzzling diet soda comes with its own set of side effects that may harm your health--from kickstarting kidney problems to adding inches to your waistline. Unfortunately, diet soda is more in vogue than ever. Kids consume the stuff at more than double the rate of last decade, according to research in the American Journal of Clinical Nutrition. Among adults, consumption has grown almost 25 percent. Kidney Problems Here's something you didn't know about your diet soda: It might be bad for your kidneys. In an 11-year-long Harvard Medical School study of more than 3,000 women, researchers found that diet cola is associated with a two-fold increased risk for kidney decline. Kidney function started declining when women drank more than two sodas a day. Even more interesting: Since kidney decline was not associated with sugar-sweetened sodas, researchers suspect that the diet sweeteners are responsible. Messed-Up Metabolism According to a 2008 University of Minnesota study of almost 10,000 adults, even just one diet soda a day is linked to a 34% higher risk of metabolic syndrome, the group of symptoms including belly fat and high cholesterol that puts you at risk for heart disease. Whether that link is attributed to an ingredient in diet soda or the drinkers' eating habits is unclear. But is that one can really worth it? The Skinny on Artificial Sweeteners Obesity You read that right: Diet soda doesn't help you lose weight after all. A University of Texas Health Science Center study found that the more diet sodas a person drank, the greater their risk of becoming overweight. Downing just two or more cans a day increased waistlines by 500%. Why? Artificial sweeteners can disrupt the body's natural ability to regulate calorie intake based on the sweetness of foods, suggested an animal study from Purdue University. That means people who consume diet foods might be more likely to overeat, because your body is being tricked into thinking it's eating sugar, and you crave more. Flatten your belly with delicious recipes. Order the Flat Belly Diet Cookbook! How to Beat Your Sugar Addiction A Terrible Hangover Your first bad decision was ordering that whiskey-and-diet-cola -- and you may make the next one sooner than you thought. Cocktails made with diet soda get you drunker, faster, according to a study out of the Royal Adelaide Hospital in Australia. That's because sugar-free mixers allow liquor to enter your bloodstream much quicker than those with sugar, leaving you with a bigger buzz. Cell Damage Diet sodas contain something many regular sodas don't: mold inhibitors. They go by the names sodium benzoate or potassium benzoate, and they're in nearly all diet sodas. But many regular sodas, such as Coke and Pepsi, don't contain this preservative. That's bad news for diet drinkers. "These chemicals have the ability to cause severe damage to DNA in the mitochondria to the point that they totally inactivate it - they knock it out altogether," Peter Piper, a professor of molecular biology and biotechnology at the University of Sheffield in the U.K., told a British newspaper in 1999. The preservative has also been linked to hives, asthma, and other allergic conditions, according to the Center for Science in the Public Interest. Since then, some companies have phased out sodium benzoate. Diet Coke and Diet Pepsi have replaced it with another preservative, potassium benzoate. Both sodium and potassium benzoate were classified by the Food Commission in the UK as mild irritants to the skin, eyes, and mucous membranes. Rotting Teeth With a pH of 3.2, diet soda is very acidic. (As a point of reference, the pH of battery acid is 1. Water is 7.) The acid is what readily dissolves enamel, and just because a soda is diet doesn't make it acid-light. Adults who drink three or more sodas a day have worse dental health, says a University of Michigan analysis of dental checkup data. Soda drinkers had far greater decay, more missing teeth, and more fillings. Reproductive Issues Sometimes, the vessel for your beverage is just as harmful. Diet or not, soft drink cans are coated with the endocrine disruptor bisphenol A (BPA), which has been linked to everything from heart disease to obesity to reproductive problems. That's a lot of risktaking for one can of pop.