Think Twice Before Drinking Diet Soda, Sure, it has no calories – but it can increase your risk of heart disease and weight gain. 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%.