Diet Soda and Your Belly

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Diet soda and your belly

Drinking diet soda, along with using zero-calorie sweeteners generally, has long been touted as a way to avoid the calories and potential weight gain that regular, sugar-sweetened soda delivers. But in the world of diabetes, the reality of diet soda has always been a bit more complicated than that. While the American Diabetes Association endorses diet soda as a beverage choice that doesn’t raise blood glucose levels, there is also evidence that drinking it raises the risk of developing Type 2 diabetes.

A new study highlights another risk that may come with drinking diet soda: an increase in abdominal (belly) fat. Published last week in the Journal of the American Geriatrics Society, the study looked at 749 adults who were age 65 or over at the start of the study. These participants were asked about their diet soda intake, and they also had their height, weight, and waist circumference measured. These measurements were taken again during three follow-up visits in the next 10 years.


According to a DailyRx article on the study, diet soda drinkers saw a small increase in body-mass index (BMI) — a measure of weight that takes height into account — over the course of the study, while diet soda nondrinkers saw a small decrease in BMI. The most pronounced differences between the groups, however, were seen in waist size. Participants who drank more than one diet soda daily saw an average waist size increase of 1.2 inches after each follow-up visit, compared with an increase of 0.69 inches in participants who drank less than one diet soda daily. Participants who never drank diet soda saw an average waist size increase of 0.3 inches at each follow-up visit. Over the course of the entire study, daily diet soda drinkers saw a waist size increase of 3.16 inches, compared with 1.83 inches for less-than-once-a-day diet soda drinkers and 0.8 inches for those who didn’t drink diet soda.

While this study offers strong evidence that diet soda can increase your waistline, it’s important to note that the lack of a randomized trial design — in which participants would be assigned either to drink or not to drink diet soda — means that factors other than diet soda intake may have led to the increased waistline seen in diet soda drinkers. In fact, it’s possible that the participants who drank the most diet soda had already experienced more weight gain than other participants, and that continued weight gain was unrelated to diet soda intake. But assuming that diet soda did lead to the increases in waist size seen in the study, these results are worrisome because, as we’ve noted before here at, abdominal fat tends to be more damaging than fat stored in other areas of the body.

Have you ever drunk diet soda in an attempt to lose weight? If so, did you succeed? Have you noticed any increase in your waistline over time, even if your body weight didn’t change much? Would you be willing to switch from diet soda to an unsweetened beverage (such as coffee, tea, or sparkling water) if further studies showed that diet soda leads to an increase in waist size? Leave a comment below!

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