Even Diet Soda Could Be Making You Fat

If you're going to indulge in soda, there's nothing wrong with the diet variety. It's just a calorie-free mix of fizzy water and delightful chemicals, right?

Well, maybe not.

Let's back up: A recent study led by the San Antonio Longitudinal Study of Aging found that men and women over the age of 65 gained inches on their waists even if they were choosing diet soda over the regular stuff.

The study surveyed 749 Mexican-Americans and European-Americans based in San Antonio for more than nine years. (At that point, a fair number of the participants had died, leaving 466 survivors.) People who didn't drink any soda, diet or otherwise, gained less than an inch on their waists between three follow-up interviews during the course of the study. Participants who reported occasional use—that is, less than one diet soda per day—had an increase of nearly two inches.

But it gets worse. People who drank at least one diet soda per day had an average increase of more than three inches.

The researchers note that this study differs from past studies because it has adjusted for other factors that could affect waistline circumference, including exercise frequency, smoking, and diabetes. This study, they say, was able to hone in on diet soda specifically.

"There is definitely debate about whether the association between diet soda intake and cardiometabolic risk … is based on an actual causal relationship," said Sharon Fowler, one of the study researchers, in a press release. That is to say, no one's sure if artificial sweeteners lead to obesity, or if there are other behaviors associated with diet soda consumption that can add inches to your belly. (While the latter may seem more obvious, there is some evidence that artificial sweeteners like sucralose can lead to weight gain.)

There is one glaring caveat for the Millennial generation, however: This study focused on seniors alone, and the most glaring examples of the soda-obesity connection were in individuals who were already obese. The researchers also acknowledge that this was an observational study instead of a randomized, controlled trial, and that their study sample was relatively small. Still, they note that these are "pretty compelling" findings that warrant further study.

Does that mean that youngins should continue to suck down diet fizzy drinks with abandon? Hardly. Nor should they be inhaling the sugar-filled kind, either.

Maybe we should all just stick to red wine instead.