The study, which was led by Dr. Sharon P.G. Fowler, examined people over age 65 for a period of nine years. During this time 749 participants were put through physical examinations and regularly asked about their daily soda consumption.
The study found that, of the 375 people who were still living roughly a decade later, the people who did not regularly consume diet soda gained an average of 0.8-inches in waist circumference. By comparison, occasional diet soda drinkers gained 1.83-inches of waist circumference. Remarkably, the study found that people who drank diet soda on a daily basis gained three inches around their waists.
Those behind the study say they took other factors–including exercise, diabetes, and smoking–into consideration.
Dr. Francisco Lopez-Jimenez, a Minnesota-based physician who was not involved in the study, says its findings “cannot be explained by the calories,” adding that it may simply be that people who drink lots of diet soda also tend to overeat. “The main point is for those who drink a lot of soda, diet or not, there may be a relationship with obesity,” Lopez-Jimenez said.
Fowler agrees. “I think it probably is true that for some people, if they are not being really hardcore about losing weight and getting a healthier lifestyle, if they switch over to diet soda that allows them to have an extra slice of pizza or a candy bar,” she said.
