- Keto breath can be a sign you've entered ketosis, which means your body breaks down fat for energy.
- Your body will usually adapt to this state in about three weeks, and keto breath will improve.
- Until then, try sipping lemon water and chewing mint leaves or sugar-free gum to freshen breath.
- Visit Insider's Health Reference library for more advice.
The ketogenic diet — keto diet for short — is a low-carb, high-fat, moderate protein diet that many folks say has helped them lose weight.
This diet works by helping transition your body from a state where it burns carbs for energy to one where it burns fat instead. This state is called ketosis.
While research does suggest this diet approach aids weight loss, one of the trade-offs is bad breath, aptly coined as keto breath.
Keto breath leaves a metallic taste in your mouth, and it can cause your breath to have an odor that ranges from fruity to an acetone-like smell that resembles nail polish remover.
What causes keto breath?
These four steps help explain why keto breath happens:
- Glucose — your body's primary energy source — is created when your digestive tract breaks down the carbs you eat.
- Cutting down on carbs forces your body to find alternative fuel sources for energy, usually fat. This is the metabolic state of ketosis.
- As your body breaks down fatty acids, it produces a byproduct called ketones, which are expelled from your body through your urine and your breath.
- One of the ketones produced is acetone, the main ingredient in nail polish remover. That's why your breath could smell like nail polish.
Eating more protein can also contribute to bad breath because the breakdown of protein creates ammonia. So, all the extra protein you're eating means a lot more ammonia in your stomach gasses that can waft up through your esophagus and out your mouth.
Not everyone on a low-carb diet gets keto breath, but if you do, keep in mind it's only temporary. It should go away once your body adapts to being in ketosis, which, according to research, takes around 21 days.
Managing it until then just takes a few simple lifestyle tweaks — here are five to try.
1. Cut back your protein
As explained above, the breakdown of protein creates ammonia that contributes to keto breath.
By eating less protein, you will reduce the ammonia that makes its way into your stomach gasses and out through your breath.
2. Drink lemon water
Increasing your water intake is a good way to help flush toxins from the body, but adding lemon may help boost the effect.
Lemon's acidity stimulates the salivary glands and increases saliva production, which can help keep your breath fresher. Lemon also has natural antibacterial properties that can further help the process.
To make lemon water, just add the juice from a wedge of lemon to one cup of water. Drink lemon water 2 or 3 times a day as needed.
A single lemon wedge contains 0.74 grams of carbs, or 0.52 net carbs.
3. Chew sugar-free gum
Gum can also help mask keto breath.
Stick with sugar-free gum — just remember to check how it's sweetened.
Many keto-friendly products use sugar alcohols like xylitol. While typically safe in small amounts, too much of these can cause unpleasant GI effects in some people. If you have IBS, even a small amount can trigger symptoms like gas, bloating, and diarrhea.
4. Chew on some mint
A no-carb, natural alternative to gum is fresh mint.
"This freshens the mouth, gums, and tongue, and also the esophagus. Also, there are no sugars or carbs in mint leaves," says Werner-Gray.
For easy access to mint leaves when you need it, Werner-Gray suggests growing a mint plant at home.
5. Drink green juice
Werner-Gray recommends drinking a green juice every day.
"Green juice such as celery, cucumber, lemon, ginger and some parsley contains the compound chlorophyll," says Werner-Gray.
Some consider chlorophyll an internal deodorant that can help reduce odor in urine and feces, but no conclusive evidence suggests it can banish bad breath.
Of course, increasing your vegetable intake is never a bad thing, though eating crunchy vegetables raw may do more for your breath than juice.
Not a fan of green juice, but still want to try chlorophyll? Buy some liquid chlorophyll and consume 8 drops at the first sign of keto breath.
Keto breath is a nuisance, but it's a side effect of being in ketosis or fat-burning mode.
That said, since fat loss is usually the goal of starting a keto diet in the first place, you might consider a few weeks of funky breath a small trade-off — especially when simple strategies like chewing mint leaves and drinking lemon water can help you manage it.