The low-carbohydrate, high-fat ketogenic (or "keto) diet continues to rise in popularity with loads of people trying the fad as a weight-loss solution.
It has even attracted the likes of celebrities Gwyneth Paltrow and Jenna Jameson who swear by its fat-cutting benefits.
However, some women have noticed some odd changes to their female region as a result — which has since been nicknamed the "keto crotch".
According to Women's Health, women's vaginas have started to emit an intense odour as a result of the low-carb diet — which was originally developed to treat epilepsy patients who were not responsive to traditional medicine.
While there are no clinical studies or research to support this claim, women have been flooding Reddit to share their "weird" experience.
One woman said that despite having lost a lot of weight and improved her gut health, she had noticed a "strange smell from down below".
"I don't have any infection or weirdness cause I went to the doctor, I shower everyday, and I keep myself very clean … but the last 2 weeks I have had this strong smell. It's not my wee because my wee is clear," she explained.
Experts claim it could be caused from a change in food consumption, as people have also complained about "keto breath".
Obstetrician and gynaecologist Sherry A. Ross explained in an interview with the Daily Mail why food can alter the odours emitted from the vagina.
"The saying 'you are what you eat' holds true to odours coming from the vagina," she said, adding that altering the number of fats and carbs in a woman's diet is not the only food change that could impact the vagina.
"Pungent foods and spices seem to take a fast lane in our bodies through the bloodstream, lungs, sweat, and vaginal secretions creating especially intense smells under arms, on the scalp, in the genital area … just about everywhere," Dr Ross told the publication.
"Foods that may give off a notably offensive odour include: garlic, onions, mint, turmeric, curry, blue cheese and other fermented foods, cabbage, cauliflower, brussels sprouts, broccoli and asparagus."
Womens Health explained that when your body was in ketosis (breaking down fat for fuel instead of carbs), it produces ketones (chemicals like acetoacetate, beta-hydroxybutyrate and acetone) — these are chemicals naturally produced by your body, but because your body produces more of them on the keto diet, the excess can make your poop, pee, and breath a little more smelly.
And since the keto diet calls for a mix of high-fat, low-carb foods with moderate proteins, it can be an adjustment for your body to get used to — and possibly cause the "smelly" side effects.
"Foods change the pH of the body. When this happens, the body will emit certain odours," Lisa De Fazio, a registered dietitian nutritionist, told The Insider.
"The keto diet (may) change your vaginal pH, which alters your vaginal odour — and it may not smell like roses," she said.
According to the nutritionist, a pH imbalance can bring upon "bad" bacteria growth, which in turn can develop irritation, odour, and infections such as bacterial vaginosis — the most common vaginal infection for menstruating people.
"The pH-balance is an important factor in maintaining vaginal health," she told the publication. "A high-fat diet, particularly saturated fat like on the keto diet, increases vaginal pH and therefore increases the risk of bacterial vaginosis."
A vagina should have a pH level between 3.8 and 4.5, which means it is moderately acidic, De Fazio said, pointing out it can vary slightly based on your stage of life.
"During your reproductive years, ages 15 to 49, your vaginal pH should be below or equal to 4.5. But, before menstruation and after menopause, a healthy pH tends to be higher than 4.5," he said.
"An acidic vaginal environment is protective. It creates a barrier that prevents unhealthy bacteria and yeast from multiplying too quickly and causing infection."
WHAT ABOUT THE MEN
Sydney-based exercise physiologist Drew Harrisberg quit the keto diet after four months, claiming it is an unsustainable and unsafe diet.
He said while he got great overall aesthetic results, he too experienced negative side effects such as bad body odour.
"I hardly had any body odour before I started keto — I then noticed my underarm odour significantly worsened," Mr Harrisberg told news.com.au.
"I am a diabetic and it affected my management really badly; I became insulin resistant.
"Unfortunately for people on keto, there's not enough science to back it up long term. I personally think it is a disastrous diet — yes, the short-term results are appealing because you do lose fat and you may look good and feel energetic with some symptoms improving, but it's so shortsighted."
Because you are consuming a huge amount of animal proteins and dairy (high fats) on a keto diet, Mr Harrisberg said it changed your gut microbiome (gut flora), which is essential to your health.
"On the diet, it changes your gut ecology to far less favourable bacteria and this in turn will change your gut and affect things like your skin and 'down there' for the ladies," Mr Harrisberg said.
After changing to a plant-based approach three months ago, the physiologist said it had reversed his body odour and contributed to other health benefits.
"My take on the keto diet is that essentially it changes your microbiome, and the changes are unfavourable for your health — that could be what's causing a flow-on effect from the high fat food, animal product consumption which then causes systemic changes," he said.