A newly conducted study revealed that people over the age of 65 who drink diet soda daily tend to expand their waistlines by much more than people who opt for other beverages. The results of the study were published online on March 17 in the Journal of the American Geriatrics Society.

Earlier conducted researches in the same age group have directly associated the drinking soda containing artificial sweeteners instead of sugar with increased risk of diabetes, metabolic syndrome and preterm birth.

Lead author Dr. Sharon P.G. Fowler of the University of Texas Health Science Center at San Antonio said the latest study only observed people over time. It didn’t test whether drinking diet soda actually resulted in gaining abdominal fat.

Fowler told Reuters Health that they can’t prove causality but there is quite a consistency in observational studies.

In order to see the role diet soda plays, researchers followed people of age 65 and above for an average of nine years. The study started with physical examination and questions about daily soda intake among 749 people who were over the age of 65 when they were first examined in 1992 and 1996.

By 2003-04, 375 participants were left alive. People who reported for further examination reported not drinking diet soda gained an average of 0.8 inches in waist circumference over the nine-year period compared to 1.83 inches for occasional diet soda drinkers.

Dr. Francisco Lopez-Jimenez of the Mayo Clinic in Rochester, Minnesota, who was not part of the study, said there can be a relationship with obesity of people who drink a lot of soda, diet or not.

Fowler said if people who are not firm about losing weight and getting a healthy lifestyle, switch over to diet soda that allows them to have an extra slice of pizza or a candy bar, this makes them consume more calories equal to what they get in regular soda.