Multiple studies have shown that the more diet sodas you drink, the greater your risk of being overweight or obese. A University of Texas Health Science Center experiment showed that adding only two cans of diet soda to your daily diet increases your risk of a bigger waistline by an incredible 500%. That is because artificial sweeteners confuse your natural ability to process calories. Put simply, consuming diet foods with artificial sweeteners makes you much more likely to overeat. Your body believes it is eating sugar, and you crave more of it.