Your Low-Carb Diet Is Giving You Disgusting Breath

bad breath dinner smell
Jason Hoffman/Thrillist
Jason Hoffman/Thrillist

A diet that consists mostly of bacon, cheese, steak, and avocados sounds like a dream. A big, greasy dream filled with all the cheddar omelets and ribeye you could want. Deliciously fatty foods usually don't scream "healthy," but many people swear by these staples to lose weight. By eliminating all sugar and most carbs, and eating foods high in fat and protein, your body becomes a fat-burning machine, or so the theory goes. Win-win, right?

Not quite. A big downside, other than missing sugar and everything in the bread family (RIP, bagels), is what these extremely low-carb diets do to your breath. By getting your energy from fat and protein rather than carbs, one of the common byproducts is intolerable stank breath, and it’s not because of the bacon grease.

What’s causing that garbage mouth?

Atkins, the ketogenic diet, and most other low-carb eating plans all rely on getting your daily calories mostly from fat and protein, and very little from carbohydrates. If you keep your carb intake to less than 30 grams per day, your body eventually enters a metabolic state of ketosis. Instead of breaking down carbohydrates to create glucose for energy, your body instead breaks down stored fat, which release ketones in the body. They are also released in your breath, creating a distinct odor that some keto enthusiasts describe as rotten fruit, or even metallic.

"I lost 114 pounds on this diet but I had BREATH like acetone," one Facebook user commented on a story about the ketogenic diet.

"I've had truly repellent, revolting bad breath," Reddit user LisaJA posted. "My friends and family have rated it about a 7 or 8 [out of] 10. My teenager has to open the car windows, it's that bad!"

The influx of ketones may be the biggest culprit of your nasty breath, but there are other factors at play, too. “The initial period of water loss in the body in the early stages of a low-carb diet can lead to dry mouth, another source of bad breath,” Dr. Wayne Aldredge, President of the American Academy of Periodontology, says.

Is there a cure for my dragon breath?

Your run-of-the-mill bad breath can be caused by a number of things, like not brushing or flossing enough, gum disease, or scarfing down a giant loaf of garlic bread. Those are all fairly treatable with some extra teeth brushing, minty gum, or actually flossing for once.

The rotten-trash-heap breath you get with a low-carb diet, on the other hand, is a whole other beast that occurs when ketones are released, not because there's more bacteria than usual. In fact, forgoing sugar and starchy foods may actually be good for your oral health.

“Foods high in sugar and carbohydrates can create acidic environments in the mouth,” Dr. Aldredge says. “The bacteria that can lead to periodontal disease thrive in these kinds of environments, feeding off of the sugar that lingers from the food we eat.”

Unfortunately, that also means ketosis breath can’t be extinguished with the typical handful of mints and swig of mouthwash. Some natural remedies may help, such as drinking extra water, or chewing on fresh mint leaves, cloves, or fennel seeds, Dr. Aldredge says. For a temporary fix, he also suggests reaching for sugar-free gum made with xylitol.

The only real cure for keto breath might come from eating more carbohydrates -- Dr. Aldredge recommends reaching for more carb-heavy fruit and vegetables for a healthier option, but too much of those may throw your body back out of a state of ketosis.

Obviously everyone’s experience on a ketogenic diet is different. If you’re one of the lucky few who's been able to remain a low-carb, fat-burning machine with perfectly fine breath, consider yourself #blessed and continue on your bacon-eating ways. But if you and your loved ones are really noticing a foul smell radiating from your mouth, you may find yourself facing a difficult choice. Losing weight on a no-carb diet is cool and all, but so is having a face-to-face conversation with a human without feeling self-conscious.

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Christina Stiehl is a health writer for Thrillist who has yet another reason to keep eating carbs. Follow her on Twitter: @ChristinaStiehl