A search for “does farting burn calories” used to bring up a seemingly plausible stat that a single fart burns 67 calories, which quickly spread online. A calculation in your head (erring on the side of generous) probably puts you at about 15 or so gas passings a day.
Does that mean you’ve really burned 1,005 calories over the course of a day just by farting? The popularity of the stat would lead you to believe that you’d stumbled upon the holy grail of life hacks.
But let’s take a step back and look at the bigger picture here before we let the air out (sorry) of that balloon.
Why Do We Fart?
Tiny bacteria in our large intestine feed on dietary fiber, some starches and sugars, and other substances the body can’t otherwise digest. This process produces gas, known as “flatus,” most of which is absorbed into our blood stream or expelled when we breathe.
But some flatus — roughly 1,500 ml a day — is expelled, becoming flatulence (a.k.a. farts).
A typical fart consists of nitrogen, hydrogen, carbon dioxide, methane, and oxygen. What’s curious is that all of these gases are largely odorless. So why do farts smell?
It comes from the less than 1 percent trace amounts of ammonia, hydrogen sulfide, and certain aminos and fatty acids. The hydrogen sulfide, particularly, is responsible for the sulfur-like smell.
The associated sound of flatulence depends on several factors, including the volume of gas expelled, tension of the muscles, and force of expulsion.
A relaxed fart will register at lower decibels than a forcible one, which is why your “home alone” blasts don’t match the “at work” squeakers.
So Does Farting Burn Calories or Not?
In short: No.
The “67 calories per fart” myth is just that. The closest you can get is straining your muscles to hold in flatulence — which is not recommended, but might burn a paltry few calories through “time under tension.” But you can’t shed pounds simply by letting it rip.
There are, however, some potential health benefits to not just the act of farting — which proves that your intestinal system is working well and its bacteria are doing their job — but the smell as well.
Remember hydrogen sulfide? Not only can it help clear a room, research has shown that its signature “rotten egg” redolence could be the key to new treatments for diabetes, stroke, heart attacks, and dementia.
A compound mimicking hydrogen sulfide’s ability to protect mitochondria is key, since preventing or reversing damage to the “cell’s powerhouse” could help not only treat these afflictions but could also help treat the overall effects of aging.
So Why Do So Many People Believe Farts Burn Calories?
Well, you just want it to be true, don’t you? Imagine being able to burn off half of the burrito you just ate on your walk to the car.
But the truth is that this “fake news” started — where else? — at the epicenter of all misinformation: Facebook.
According to a Snopes investigation into the phenomenon, a Facebook page called “F A C T” posted the claim in November of 2015, and it took off from there. F A C T’s source for the information, which quickly became a top Google result, seems to have been… Google.
So in a kind of odd circle of lies, a Google search based on nothing became a fake fact thanks to Facebook which quickly became a top search result on Google.