We are tempted to choose diet soda, because we think is fat-free and zero-calorie. “People are under the impression that they’re healthy, and they’re really not,” says Druz. Cola has heart-disease risk factors such as obesity and diabetes. Studies have shown that people who consume diet sodas tend to overcompensate and drink or eat more calories than they otherwise would. “While it may have no sugar, it’s not a heart-healthy choice,” says Druz.