Ditch diet soda to lose weight You should ditch all soda, including diet. Research from the Johns Hopkins Bloomberg School of Public Health revealed that overweight and obese adults who drank diet beverages ate more calories from food than those who drank regular soda. Additionally, a University of Texas study found that diet soda drinkers had a 70% greater increase in waist circumference than non-drinkers over the course of about 10 years. "In addition, many people think 'low-fat,' 'low-sugar,' or 'light' means fewer calories, but that's not always true," says Goodson. "Typically when manufacturers cut something out and the end result tastes just as good, they've added something like additional sugar."