You’re alone in the comfort of your home, so naturally, you let one rip. No shame. But the smell of your own fart is taking over, and the stench is creeping up and suffocating you. Now you’re trapped in your own foul odor — this wasn’t expected! Why is this fart disgusting, when others pass without making their presence known?
Then, as if the heavens parted, the stench disappears. You look around, double-checking that no one is home, then go back to your normal life, safe from suffocation by flatulence.
Why did your fart smell like rotten eggs at the bottom of a New York City trash heap? Was it something you ate? Is there something wrong with you, internally? Do you have a superpower you didn’t know existed? Dr. Myron Brand, a gastroenterologist at Connecticut Gastroenterology Consultants, helps set the facts straight.
What causes farts to smell?
YOU. You have the power to control your own gruesome odor by what you eat — not all farts are created equal. Some smell like bitter alcohol, others smell like three-month-old expired broccoli, and many smell like the aforementioned rotten eggs.
“Smelly odor is not bad, it’s just a function of what you’re eating and what your bacteria is doing inside your gastrointestinal tract. Everyone is different,” Dr. Brand explains. “Foul smell just means the carbohydrates you consume are being malabsorbed — it’s fermented.”
Ironically, the healthier the food you eat, the worse the smell. Fiber-rich foods, such as broccoli, Brussels sprouts, and quinoa, boost gut bacteria, and in return cause you to naturally pass gas. Foods with high sulfur composition, such as red meat, milk, or plant-based proteins, are the culprits of producing the foul odor. When we feed the bacteria in our gut high-protein foods, they produce a sulfur gas, which makes your farts noxious, says Dr. Brand.
“The end product of fermentation in our gastrointestinal tract is gas — carbon dioxide, hydrogen, or methane. And it’s all made from bacteria fermentation.”
But hey, it’s a small price to pay for being healthy… or is it?
So what’s with the rotten egg smell? That sounds like something to be alarmed about.
When the bacteria in your gut break down all that food into hydrogen sulfide, then you produce that ghastly rotten egg fart smell.
“Some people are methane producers, and some people are hydrogen sulfide producers — which causes flatulence to smell like rotten egg. It’s all a function of what you eat,” adds Dr. Brand, helpfully reminding you that eating a steady diet of cabbage and cheeseburgers is bad on virtually every level. The common thread between rotten eggs and farts is the sulfur; if you’ve ever been to natural springs that emit sulfurous gasses, you probably recognized the stench. It may be the only thing your butt, eggs, and natural hot springs have in common.
Is it preventable?
If you have to choose based solely on how much you’ll fart, Dr. Brand recommends going high-protein. “Proteins won’t cause a lot of gas, but carbohydrates will.”
There are more extreme measures you can take, too, though it’s important to understand that what works (or goes horribly wrong) for you may do the opposite in someone else. “As a doctor, you try to manipulate this occurrence with things like the FODMAP diet or probiotics,” Dr. Brand says, which is a science-y way of saying every person is different and it’s a bit of a guessing game as to which foods make one person rip silent-but-deadlies and another go about their day without emitting a hint of methane.
The low-FODMAP diet he mentions is one that limits certain types of carbohydrates that have a tendency to ferment in your gut and, as you now know, produce rancid gas. This diet is tough to follow, since it eliminates seemingly healthy foods like onions and asparagus, so it’s typically used only for people with serious gastrointestinal distress. If your flatulence is really an issue, work with a gastroenterologist or dietitian to pinpoint which carbohydrates are the cause of your discomfort or bloating. You can also check this quick primer on high-FODMAP foods vs. low-FODMAP foods, with low-FODMAP foods being the ones less likely to ferment.
Is it a bad thing?
Eh, not really, unless you surround yourself with people who judge you solely based on your farts, in which case you might want to rethink your friend group. You live in a symbiotic relationship with your gut bacteria — you have to feed them if you want to achieve optimal health. The average (healthy) person farts 10-20 times a day. So farting is normal.
If you continually drive people away with your potent superpower, though, it may be time to see a professional. Usually, though, a fart is a fart is a fart that won’t kill you. “Unless it’s excessive, because that’s a sign that you’re malabsorbing and not digesting carbohydrates,” you’re probably fine moving on with your life, Dr. Brand advises.
So is the rotten egg fart really a shameful odor?
Nope. It just means you’re eating food and digesting it well — and there’s more room on the outside than on the inside.