13 hours ago

Sofia Quaglia

Serenity Strull/ Getty Images

Garlic, alcohol, meat and even fasting can affect our body odour – and alter how appealing our scent is to others.

Each one of us has a unique scent profile, like a fingerprint. Everything from our personality type – such as extroversion, dominance and neuroticism – to our mood and health affects the way we smell.

“The past few decades have revealed that odour is shaped by our genes, hormones, health, and hygiene,” says Craig Roberts, professor of social psychology at University of Stirling in Scotland. “Whether we are male or female, young or old, gay or straight, dominant or subordinate, ovulating or pregnant, sick or well, happy or sad.”

Many of these factors are out of our control – but not all. A significant influence on the way we smell is the food we eat. Not only does this affect our overall aroma, but also how we are perceived, including how attractive we appear to others, according to a small but growing body of research.** **

Breath and sweat

On a biological level, food affects our body odour by two main routes, says Lina Begdache, an assistant professor of health and wellness studies at the State University of New York at Binghamton. Those are our guts and our skin.

First, the gut. As you digest your food, bacteria are at work metabolising it inside your gut. Some of those interactions between food chemicals and bacteria release gases – volatile molecules that make it out of your body the same way the food went in, says Begdache. This can result in bad breath, or halitosis, especially depending on what you eat (more about this later). Data suggests that about one-third of adults worldwide suffer from some form of halitosis, though there are other causes besides digestion.

Getty Images

Perhaps the most obvious way food affects our odour is in our breath, but it can also alter the smell of your sweat (Credit: Getty Images)

Second, the skin. Chemical components from your food, once metabolised, also travel through the bloodstream and many of the body’s tissues. Some end up being perspired through the skin, where they interact with the skin’s bacteria and create a smell there, too. (Yes, sweat in itself is odourless; it’s the skin bacteria that thrive in sweat that makes sweat smelly.)

Different foods have a variety of chemical compounds that come into play at different stages, resulting in varying levels of stink. But the foods with the most pungent results almost always have one culprit in common: sulphur. Surprisingly, though, some studies do suggest these odorous compounds can have an unexpected effect of making us more attractive.

Fruit and vegetables

Broccoli, cabbage, Brussels sprouts and cauliflower may be staples of a healthy diet – but they are heavily packed with sulphurous compounds, which can often be reminiscent of the smell of rotting eggs. When these compounds make their way through the bloodstream and interact with skin bacteria, your sweat can turn into a strongly pungent liquid, according to nutritional therapist Kerry Beeson.

Foods from the allium family, such as garlic and onions, can also affect the smell of our sweat and breath for the same reason as cruciferous vegetables: when they’re metabolised by the human body, they break down into stinky compounds like diallyl disulphide and allyl methyl sulphide, which are emitted by your body in slightly different timelines – right after ingestion and then, in the case of allyl methyl sulphide, with a peak 30 minutes later.

Surprisingly, though, studies suggest that while garlic definitely makes people’s breath smelly, it makes people’s armpit sweat more attractive. Scientists had 42 men wear armpit pads collecting their sweat for 12 hours, while some of them ate a little bit of garlic, some ate a lot of garlic and some took garlic supplements. Then, 82 women rated the scent collected from those pads according to subjective ratings of pleasantness, attractiveness, masculinity and intensity. The men with little garlic consumption didn’t illicit a huge reaction, but those eating a lot of garlic were perceived as very sexy. And those taking supplements were also more attractive.

Carb-heavy diets produced the least sexy of scents

“We replicated this study three times because we were really surprised,” says the scientist behind the experiment, Jan Havlíček, who studies human ethology and chemical communication at Charles University in Czech Republic. Since garlic has antioxidant, antimicrobial properties that improve people’s health, he speculates that’s what might be making these men’s scent more pleasant to women.

Getty Images

Men who consume more fruit and vegetables have a more floral and sweet scent (Credit: Getty Images)

Other vegetables have a very unique effect on our smell. The asparagus plant produces a compound called the asparagusic acid and, when it’s digested by your body, it releases sulphur compounds too. It’s these chemicals, such as methanethiol and dimethyl sulphide, that make your sweat and your pee smell a certain way. Sulphur compounds are very volatile, so they easily disperse in the air. That’s why they’re so easy to smell from the toilet bowl. This smell usually lasts more than five hours.

Not everybody produces this smell, although studies about this keep coming up with different findings. In the 1950s, research seemed to suggest that fewer than 50% of people produce the tell-tale asparagus pee odour, while in 2010, researchers found more than 90% of test participants did. So it’s not clear cut. And not everybody can perceive the stink: the ability to smell one’s pungent asparagus-smelling pee seems to be down to genetics too.

However, when it comes to fruit and vegetables more widely, eating more of them can lead to a more attractive scent. A 2017 study in Australia found that men who had consumed more fruit and vegetables were significantly associated with smelling better – more fruity, floral and sweet.

The study also notes, interestingly, when people have to rate people’s faces, slightly yellower skin rich in carotenoid – a molecule from carrots, pumpkins, tomatoes and papayas and others – is also found to be more attractive. But the same study suggests that people consuming diets with a little bit of fat, meat, egg, and tofu intake were also associated with more pleasant-smelling sweat. Carb-heavy diets produced the least sexy of scents.

Meat and fish

Meat and fish can also produce a distinct body odour as animal proteins are broken down by the body into amino acids and fats, which are then excreted through sweat – where they interact with skin bacteria.

Fish and beans, for instance, can cause body odour because they’re filled with trimethylamine, a very strong-smelling compound. There’s even a health condition, called trimethylaminuria – also known as “fish odour syndrome” – which arises when the body can’t turn trimethylamine into a non-smelly compound, says Beeson. “This can lead to a strong body odour,” she says, but this condition is quite rare. For instance, a 2025 case report recounts a 10-month-old boy who developed trimethylaminuria and began smelling like rotting fish after eating fish including swordfish. The condition was transient, and through careful management he was eventually able to eat fish without the symptoms reoccurring.

Getty Images

People who have meat-free diets are often rated as being more attractive (Credit: Getty Images)

Another study of adult men from 2006 by Havlíček’s team can offer insights about whether meat makes us more attractive. The scientists looked at 30 men who were either eating a meat or non-meat diet for two weeks. Women rated their scent for their pleasantness, attractiveness, masculinity and intensity. The odour of the men on meat-free diets was on average rated as more attractive, more pleasant and less intense.

“To our surprise, those who were eating meat smelled slightly worse than when they were not eating meat,” says Havlíček.

This was not what he was expecting to find, because meat is considered an important part of the human diet throughout evolution. However, no early human was eating as much meat as is common in today’s complex, industrialised society. “It’s something which was not common during our evolution, to eat meat every day,” says Havlíček.

Alcohol and coffee

Alcohol – especially consumed in large amounts and at regular intervals, says Begdache – can cause bad smell both from the gastrointestinal tract and from the sweat glands. When your body processes alcohol by breaking it down inside the liver, it releases a compound called acetaldehyde, a toxic and volatile compound, which has a strong, recognisable scent of stale booze. (One study showed police officers could tell if people had drunk just from their mouth odour between 60 and 85% of the time, depending on how much they had had.) And since alcohol makes you dehydrated and reduces your saliva flow, it allows for more bacteria to hang around in your mouth, causing bad breath to persist.

One study noticed, for instance, noted that out of 235 people the people who consumed alcohol daily were most likely to complain about bad breath, and have higher concentrations of volatile sulphur compounds in their breath. Another study from 2010 studied men who drank beer during an experiment and those who drank water instead. They found that the beer-drinkers were more attractive – but sadly only to mosquitoes.

Caffeine found in coffee and tea, meanwhile, can stimulate the apocrine glands, which are responsible for producing sweat in areas like the armpits and groin. This increased sweat production can create a more favourable environment for bacteria to thrive, potentially leading to stronger body odour, says Beeson. Plus, one study showed that caffeine molecules can be found all the way in sweat too – but there’s no data about whether the caffeine itself affects body odour.

Beer-drinkers were more attractive – but sadly only to mosquitoes

“We are mammals, and like all mammals, odour almost certainly has an important influence on social interaction,” says Roberts, who studies scent and social interactions.

Scent is just one of a vast range of factors that influence how attractive people find us. It’s extremely challenging, “if not impossible”, to isolate the effects of smell from these other social cues, such as how people look, behave and talk, says Roberts.

But still, even the science meticulously measuring these ethereal, subtle changes has been coming up with contrasting findings.

For instance, Havlíček also did an experiment where men rated women on their armpit sweat pad’s scent for their pleasantness, attractiveness, femininity and intensity, after some women ate as normal, and others fasted for 48 hours. While there wasn’t a huge divide between the groups, the fasting women did have more attractive sweat than the women who didn’t. “This was again something we didn’t expect,” says Havlíček.

But these results would need to be replicated to help paint a clearer picture. And, while your sweat may smell better, one 2018 study in Switzerland found found that fasting made people’s breath smell worse.

If anything, the constant surprise arising from their study results has led researchers like Roberts and Havlíček to realise that there’s no one clear formula for how food affects our body odour and perception. There’s a lot of variability.

“There are plenty of aromatic compounds, and in most of them we don’t know how they influence our body odour, but there is a high probability they do,” says Havlíček.

–

For trusted insights into better health and wellbeing rooted in science, sign up to the Health Fix newsletter, while The Essential List delivers a handpicked selection of features and insights.

For more science, technology, environment and health stories from the BBC, follow us on Facebook and Instagram.