Could Carbonation Be Keeping You Up at Night — and Dooming Your Diet?

By Kevin Kolodziejski

Uri Geller I’m Not

I will make no attempt to bend a metal spoon because of it. I won’t even start playing the Pennsylvania lottery. But I may possess some strange sort of eater’s ESP, based on research I stumbled upon about three weeks ago.

Last year I was facing a problem that’s probably a puzzler for other old-timers who still worship at the altar of Eddy Merckx and “ride lots”: How to drink enough in the summer to be fully hydrated for the next day’s ride, yet not wake up every hour on the hour? In the search for a solution, I learned carbonation can increase the rate and frequency of late-night urination.

While I enjoy ice-cold water first thing in the morning, I barely tolerate the tepid stuff I drink from a water bottle on a late-morning ride. That may be why I want taste to my beverages after that. Along with stevia-sweetened decaffeinated tea, I drink sugar-free flavored sparkling water during the remainder of the day.

And I need to drink a lot of fluid. On a hard and long ride in the worst heat and humidity a Pennsylvania summer has to offer, I can easily lose 6 to 8 pounds. Yes, I’m aware that multiple studies have shown exercise performance is adversely affected by as little as a 2-percent loss of body weight, that a 5-percent loss decreases the capacity for work by about 30 percent, and that I should drink more on hot rides, but I still can’t force down any more than a bottle and a half, tops.

So last summer I applied common sense to my situation and started drinking my sugar-free flavored sparkling water flat. Surely enough, that reduced my middle-of-the-night bathroom trips to a more manageable number.

Common Sense — Or a Sixth One?

Time for full disclosure: I’m as far from a spendthrift as you can get. Both of my wind trainers — and every single one of my ties — were purchased in the prior century. Since the carbonation has to be a considerable part of flavored water’s cost, I initially dismissed the idea of defizzing it. The miser in me saw doing so as a waste of money.

But like bibs outstretched just enough so that you think about them too often as you ride, I couldn’t shake the sensation that there was another reason besides a decent night’s sleep to defizz my flavored water. In part, that’s why I started screwing off the caps to the bottles before chilling them. And then about a month ago, I stumbled upon what could be the extrasensory explanation for that unshakeable sensation. In “Zero weight loss from zero calorie drinks? Say it ain’t so,” Robert H. Shmerling, MD, and Senior Faculty Editor of the Harvard Health Publishing website, cites a study that links carbonation to an increase in appetite and weight gain.

An ‘X-Files’ Episode Takes Shape

As I went to check my daily food log from last year, I swore I heard the theme song from “The X-Files” in the distance. Maybe the melody was just in my head, but there was no way to dismiss what was on the page — in all capital letters and underlined in red — after the day’s totals for calories, protein, and fiber. A note that I had eaten at least 200 fewer calories than normal in the last few days that ended with a question: “Why don’t I feel as hungry all of a sudden?” I turned the log back six days and found another addendum.

I had started drinking my sugar-free flavored sparkling water flat on that day.

Okay, so it’s not nearly as impressive an example of ESP as the suddenly panicked guy who runs off the plane only to watch it crash at takeoff, but the protocols of the aforementioned study published in the 2107 Sep-Oct issue of Obesity Research & Clinical Practice are certainly worth your consideration.

Carbonation Increases Production of the Hunger Hormone

For more than a year, researchers gave three groups of male rats one of three beverages: water, typical soda, or diet soda. A fourth group was given typical soda allowed to go flat. Regardless of whether the carbonation came from typical or diet soda, the rats consuming it ate more food than the rats given water or flat soda. They also gained weight faster. Moreover, the researchers detected a hormonal reason for both: elevated levels of the hunger hormone, ghrelin, in the rats whose drinks contained carbonation.

That led the researchers to see if a similar increase occurs in humans.

On different days over the course of a month, 20 males drank one of the four drinks previously given to the rats or carbonated water. The subsequent tests for ghrelin found increased amounts of it after the 20 drank any type of carbonated beverage. The study authors theorize that an increased pressure in the stomach from carbonation causes an increase in ghrelin production. They end the paper by stating their results “implicate a major role for carbon dioxide gas in soft drinks in inducing weight gain and the onset of obesity via ghrelin release and stimulation of the hunger response in male mammals.”

Even odder than my episode of eater’s ESP is that I never read about this study until three weeks ago. What I have read ad nauseam, though, are studies to determine if the artificial sweeteners used in carbonated diet sodas undermine or even produce weight gain — but no consensus has come from them. For every study that suggests the use of aspartame or sucralose or saccharin creates weight gain, there’s one to contradict that.

Maybe what’s really at play here is a combination of what was detected in the carbonated-beverage study and what those seeking advice from me hear — ad nauseam. That our metabolic systems are all a bit different, so the only way to know if any dietary discovery is true for you is to become your own lab rat.

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Kevin Kolodziejski began his writing career in earnest in 1989. Since then he’s written a weekly health and fitness column and his articles have appeared in magazines such as “MuscleMag,” “Ironman,” “Vegetarian Times,” and “Bicycle Guide.” He has Bachelor and Masters degrees in English from DeSales and Kutztown Universities.

A competitive cyclist for more than 30 years, Kevin won two Pennsylvania State Time Trial championships in his 30’s, the aptly named Pain Mountain Time Trial 4 out of 5 times in his 40s, two more state TT’s in his 50’s, and the season-long Pennsylvania 40+ BAR championship at 43.