Put Down the Diet Soda, Grandpa: Zero-Calorie Drinks Linked to Health Risks for Seniors

Research finds that older Americans who regularly drink artificially sweetened beverages are adding inches to their waistline.

(Photo: Mark Edward Atkinson/Tracey Lee/Getty Images)

Mar 19, 2015· 2 MIN READ
Jason Best is a regular contributor to TakePart who has worked for Gourmet and the Natural Resources Defense Council.

Looks like it’s time to convince Grandma to kick her Diet Coke habit. In the latest bit of dismal news for the soda industry, another scientific study has found virtually zero health benefits to drinking zero-calorie diet soda. In this instance, older Americans who regularly consumed diet soda were more likely to pack on excess pounds around their belly, increasing their risk for heart disease and metabolic syndrome.

“Calorie free does not equal consequence free,” Sharon P.G. Fowler of the University of Texas Health Science Center at San Antonio tells Reuters. Fowler led the study, which was published this week in the Journal of the American Geriatrics Society.

Researchers looked at data that had been collected back in the mid-1990s at the outset of the San Antonio Longitudinal Study of Aging, which involved nearly 750 adults age 65 or older. Among other questions, participants were asked about their diet soda consumption, and their height, weight, and waist circumference were measured. Some 375 participants returned for the last of three follow-up visits in 2003–04.

Among the remaining participants, Fowler and her team found that while those who never drank diet soda saw an average increase in their waist circumference of .8 inches, those who occasionally drank diet soda gained more than twice as much, and those who drank it daily increased their belly size by a belt-busting 3.16 inches—a nearly fourfold gain over nondrinkers.

The study controlled for factors such as physical activity and smoking.

What it doesn’t do, Fowler emphasizes, is prove that the diet soda caused the bigger bellies. “We can’t prove causality, but there is quite a consistency in observational studies,” she tells Reuters.

Indeed, a growing body of research has linked consumption of diet soda and other artificially sweetened beverages to weight gain and other ill effects. A 2008 study out of the University of Texas, for example, found that people who regularly drank such beverages were twice as likely to become overweight or obese than those who didn’t. A 2014 study from Johns Hopkins University reported that adults who drank artificially sweetened beverages consumed more calories overall per day than those who didn’t.

For her part, Fowler thinks there’s some twisted dieter’s logic to that. “I think it’s probably 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 tells Reuters.

Yet while the explanation of “I’m drinking diet so I can indulge in a bigger slice of cake” continues to have its adherents among researchers and public health experts who are trying to figure out why drinkers of diet soda appear to gain more weight, other theories have emerged as well. Some experts have suggested that artificial sweeteners mess up our brain chemistry in a way that ends up causing us to crave more sugar, while an intriguing study published last September linked consumption of artificial sweeteners to changes in gut bacteria that were associated with obesity.

Even as the science surrounding artificial sweeteners and weight gain remains in flux, there’s one zero-calorie beverage that experts agree is better than all the others: water.