Why does my poop smell sweet after COVID

A few weeks after he began getting out of bed, Burke was still feeling fatigued and suffering from migraines. His vision declined and he couldn’t sleep. His sense of smell remained faded and distorted, though he could taste salt and sugar. He began to wonder if he was a “long hauler,” a Covid-19 survivor who experiences persistent symptoms.

For those who work in the food industry, lingering anosmia and parosmia can be particularly debilitating. Chefs and bakers rely on their palates to fine-tune recipes and taste-test dishes, and without a sense of smell, those tasks are almost impossible. While it’s not yet clear whether Covid-19-related anosmia is ever permanent, the unknowns add a layer of anxiety to the equation. Several food industry professionals I interviewed for this story described smelling everything in the kitchen many times a day just to see if anything had changed.

“Yes, I’m very grateful I’m alive, but there are all these things that are happening to us afterwards that are still traumatic and life-altering,” Burke said. “The simple pleasure of eating or smelling something—it feeds into your mental health and wellness. And if that’s declining, there’s no opportunity for you to recover from the other symptoms because it’s just manifesting into the spiral of darkness.” 

When tasting is your job

For Burke, the ongoing inability to smell and taste meant he fell behind on work. During the pandemic, his freelancing work had picked up as publications sought out recipes for home cooks. He had been shopping around a cookbook proposal. All of that ground to a halt. 

“I couldn’t even get myself motivated to go into the kitchen,” he said. “I didn’t trust my palate or my body or my mind, honestly,” he added. He worried his career was over. 

Filitsa Gray, owner of a vegan baking business in London, lost her sense of smell and has found it difficult to develop new recipes.

Filitsa Gray runs a vegan baking business from her London home. Almost three years ago, she quit her job to bake full-time. Things were going well: She’d built a loyal customer base, and she loved what she did. 

“As a baker, you get that nice homey feeling when you’ve got fresh cookies. That smell of chocolate coming out of the oven—it’s almost better for me than eating the hot cookie,” she said. 

She lost her sense of smell earlier this year. Then, on July 26, it came back all at once, albeit “really weird. All my food tasted like plastic bags,” she said. At first, she continued to cook, following her recipes closely and relying on her boyfriend to taste her bakes. Then she began Googling her symptoms. Parosmia wasn’t yet a verified symptom of Covid-19, but she found a Facebook group run by the charity AbScent that lent a name to the condition. “I had a mini-breakdown because I was like, ‘Oh my God. I can’t deal with this for 15 years,’” as her mother once had. 

Since the parosmia began, she’s been eating vegan cheese sandwiches two or three times a day because they’re one of the only foods that don’t trigger her symptoms. She buys white bake-at-home baguettes and half-bakes them for five minutes; any longer in the oven and they start to brown, the beginning of the Maillard reaction, one of the most commonly reported parosmia triggers. “If you burn toast and scrape all the black char off the toast, then throw that toast back in the wooden fire and put burnt toffee sauce on the top, that’s what it tastes like,” she said. 

The parosmia has affected her professionally, too. She finds it difficult to develop new recipes. She tested most of the dozen treats she included in her Christmas boxes “blind,” reminding herself that apples don’t taste like soap to everyone. She struggles with whether to tell her clients what has happened to her.

A survey by Fifth Sense, a U.K. charity for people with smell and taste disorders, found that nearly 57 percent of people suffering from anosmia or parosmia report feeling isolated because of their condition. More than 40 percent report feeling depression, and 92 percent of respondents say their condition has negatively affected their appreciation of food and drink. 

“Depression and olfactory function go hand in hand,” said Dr. Jane Parker, a flavor chemist at the University of Reading in England. “If you’ve got no olfactory function, you get depressed. But if you get depressed, your olfactory function is diminished. They are very intertwined,” she said. 

For the time being, Gray is focusing on the positive. She’s paying extra attention to the decorations on her cakes and cookies, adding even more visual and textural appeal to her work. She’s developing bake-at-home and decorate-at-home boxes for customers stuck in lockdown. She sold out of Christmas treat boxes twice, even though she couldn’t enjoy them herself. 

“Every day, you have to keep trying and moving forward and hoping this won’t last forever,” she said. “When you concentrate on what you can’t eat, that’s when you start getting sad, getting down into a deep hole.” 

The parosmia test

At The Flavour Centre, a University of Reading lab outside of London, flavor chemist Jane Parker directs study participants toward a machine that looks a little like an oven with a hose snaking out of it and a nose piece on the end. Before the pandemic began, Parker suspected parosmia might be triggered by specific chemical compounds, so she began inviting parosmics to undergo a series of tests. 

The machine that tests parosmics is a gas chromatograph. Food writer and Nose Dive author Harold McGee compares the machine to a still. As the chromatograph heats samples—in Parker’s tests, usually coffee—it pipes individual groups of molecules through the hose. The study participant on the other end of the line experiences each emission as a different aroma, rather like the individual ingredients in a recipe.  

Over the course of a session, the gas chromatograph might release a new aroma every few seconds.

Loss of sense of smell is one of the most common symptoms of COVID-19, per the Centers for Disease Control and Prevention (CDC). But some people with COVID-19 experience another smell-related complication: a smell distortion called parosmia.

"While anosmia is a complete loss of smell and hyposmia is a decreased sense of smell, parosmia is an alteration of the sense of smell," Seth Lieberman, MD, assistant professor in the department of otolaryngology at NYU Langone Health, told Health.

About 10% of people who experienced olfactory (smell) issues during COVID-19 may develop parosmia as they begin to recover, per an April 2022 paper published in the journal Foods.

The "COVID smell" typically occurs two to three months after you had COVID-19, even if you didn't lose the sense of smell when you had the disease, per a February 2022 paper published in the journal Current Opinion in Otolaryngology & Head and Neck Surgery. But it can also start earlier, per a July 2022 paper published in the journal Laryngoscope.

The smell distortion is not a change for the better. People with parosmia say that everything smells unpleasant, even rotten or disgusting. "A piece of fruit may smell like chemicals, or even worse, like fecal matter," Dr. Lieberman said.

According to the July 2022 paper, parosmia is a "misperception of odors (such as perception as rotten or burnt odor)." Its causes include upper respiratory tract infections, head trauma, and neurodegenerative diseases such as Alzheimer's disease. Foods like coffee, onion, meat, citrus, or garlic can trigger parosmia attacks, per the February 2022 paper.

Parosmia often develops shortly after anosmia and/or hyposmia—and it's been shown to develop after COVID-19. The olfactory condition can greatly affect a person's quality of life, per the July 2022 paper.

Parosmia affects some people with COVID-19, but's not a symptom of the early stage of the disease. Parosmia may be a sign that you've recovered from COVID-19 completely, per the April 2022 paper.

Parosmia is not common in people who've had COVID-19 overall. But it is common among those who've experienced smell issues during COVID-19—about 64% of participants in the July 2022 paper with post-COVID-19 smell dysfunction had parosmia.

"It is believed to be due to an impact of the infection on the olfactory nerves' ability to interpret odors and aromas, and it can be seen in the aftermath of other types of viral infections," Charles Bailey, MD, medical director for infection prevention at Providence Mission Hospital and Providence St. Joseph Hospital in Orange County, California, told Health.

Recovery of sense of smell seems to depend to some extent on nerve regrowth, Dr. Bailey said. That means there may be little that can be done to accelerate the process.

The July 2022 study showed that Modified Olfactory Training (MOT) for 36 weeks was effective in treating post-COVID-19 parosmia. This training involved smelling certain scents—such as those of eucalyptus, lemon, clove, and rose—multiple times for 10 seconds with a 10-second breaks in-between. The training took up five minutes and was meant to be performed twice a day. The selected scents changed every 12 weeks.

An April 2022 paper published in the British Medical Journal (BMJ) noted that "there are currently no effective, evidence based treatments for patients with parosmia." But they did offer some practical management tips for those with the smell distortion:

• Keep track of foods that trigger your parosmia and let the people around you know what they are.
• Because parosmia triggers can change, keep trying new things to find what your "safe" foods are.
• Consider eating foods that are cold or at room temperature—they give off less odor.

Parosmia can greatly affect people's experiences with food and other smells, and it may last for a while. The April 2022 BMJ paper recommended being open about the condition to others so they can support you in avoiding major triggers. And remember that parosmia severity can fluctuate and make you feel worse some days than others. These fluctuations even out eventually.

If your parosmia is severe enough that you can't eat most or any foods, talk to a healthcare provider or dietitian.

The information in this story is accurate as of press time. However, as the situation surrounding COVID-19 continues to evolve, it's possible that some data have changed since publication. While Health is trying to keep our stories as up-to-date as possible, we also encourage readers to stay informed on news and recommendations for their own communities by using the CDC, WHO, and their local public health department as resources.

Thanks for your feedback!