Updated on February 22, 2024
4 min read

What is Keto Breath? Why It Happens and How to Fix It

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Key Takeaways

  • Ketones are a byproduct of entering ketosis, a metabolic state brought on by the low-carb diet known as keto
  • Keto breath happens when your body excretes ketones through exhalation
  • Keto breath may smell or taste metallic, fruity, or like nail polish remover
  • It develops within a few days or weeks after you start eating keto and will subside after weeks on the diet
  • You can make keto breath go away by adjusting your diet, drinking more water, and using breath fresheners

What is Keto Breath?

Keto breath is a distinct taste or odor in the mouth that comes from eating a ketogenic or low-carb diet. The symptoms of keto breath include:

  • Metallic taste
  • Overly sweet, like rotten fruit odor
  • Chemical odor, like nail polish remover

The taste or smell is a side effect that often occurs when you first start eating keto or low-carb. Not everyone who eats a low-carb diet will develop keto breath. For those who do, it’s typically temporary.

salad and avocado with flowers placed on wooden table

What Causes Keto Breath?

When your body goes into ketosis, it has two ways of excreting the high levels of ketones it produces:

  • Exhalation
  • Urination

Because of this, you may notice a change in your breath and urine. These changes signal that you’ve entered ketosis.

Keto breath usually becomes noticeable within a couple of days or weeks of starting a keto or low-carb diet. It will likely subside after a few weeks once your body gets used to the new diet.

Can You Prevent Keto Breath?

Because keto breath is a byproduct of the metabolic process, there’s no real way to prevent keto breath. The only way to completely eliminate it is to switch your eating style or wait for it to subside.

If you’re concerned about developing keto breath, you can use a ketone breath analyzer to determine how many carbs you can eat without leaving ketosis. That way, you can increase your carbs to offset bad breath while still getting the effects of ketosis.

Home Remedies For Getting Rid of Keto Breath

Although there is no way to prevent keto breath, there are a few ways to keep your breath smelling and tasting better until it goes away.

These include:

1. Drink More Water

Drinking water can help flush out the ketones more quickly through urination. It can help prevent or improve bad breath.  Staying hydrated will also help alleviate dry mouth, which can be a side effect of keto.

2. Tweak Your Macros

Adjusting carbs, fat, and protein intake can help reduce keto breath. Eating high amounts of protein can worsen your breathing by producing odorous ammonia. 

You can also increase your carb intake to improve your breath. Only bump up your carbs slightly if you want to stay in ketosis.

3. Use Breath Fresheners

You can mask the unpleasant odor and taste with chewing sugar-free gum, mints, and mouth spray. These won’t fix the problem, but they can improve things until keto breath goes away on its own. Always check the sugar and carbohydrate content of whatever fresheners you use to ensure they’re keto-friendly.

4. Herbal Tea

Various herbs are available which can be used as a natural breath freshener. You can add the following herbs to water and tea:8

  • Clove
  • Cinnamon
  • Mint
  • Fennel 

5. Practice Good Oral Hygiene

Paying special attention to your oral hygiene routine can be beneficial for keto breath. Brush at least twice a day, floss once daily, and use an alcohol-free mouthwash regularly to keep your mouth clean of bacteria.

6. Give It Time

Keto breath isn’t permanent. Once your body gets used to ketosis, the odor and taste should disappear. Be patient, and your breath will return to normal within a few weeks.

What is the Keto Diet?

The ketogenic diet, also known as keto, is a popular low-carbohydrate, high-fat, and high-protein diet. Many people use it to lose or manage weight.3 People on a keto diet commonly eat foods like:

  • Meat and eggs
  • Seafood
  • Non-starchy vegetables and low-sugar fruits
  • Full-fat dairy
  • Nuts and seeds

Keto focuses on replacing carbs with fats in an effort to trigger a metabolic state called ketosis. During ketosis, your body produces ketones in the liver to help you burn fat for energy.

Some people adapt relatively quickly to a state of ketosis, but others do not. You must be careful when changing your body’s metabolic state. If you’re curious about trying keto, speak with your doctor to assess whether it’s the right choice.

Other Oral Health Side Effects from the Keto Diet

Going on a keto diet can also lead to various symptoms that affect you and your oral health. These include:7

  • Increased thirst
  • Dry mouth
  • Decreased hunger or appetite
  • Frequent urination

Last updated on February 22, 2024
8 Sources Cited
Last updated on February 22, 2024
All NewMouth content is medically reviewed and fact-checked by a licensed dentist or orthodontist to ensure the information is factual, current, and relevant.

We have strict sourcing guidelines and only cite from current scientific research, such as scholarly articles, dentistry textbooks, government agencies, and medical journals. This also includes information provided by the American Dental Association (ADA), the American Association of Orthodontics (AAO), and the American Academy of Pediatrics (AAP).
  1. Woelber et al. “An oral health optimized diet can reduce gingival and periodontal inflammation in humans – a randomized controlled pilot study.” BMC Oral Health, National Library of Medicine, 2016.
  2. Batch et al. “Advantages and Disadvantages of the Ketogenic Diet: A Review Article.” Cureus, National Library of Medicine, 2020.
  3. Masood et al.Ketogenic Diet.” StatPearls, National Library of Medicine, 2021.
  4. Crosby et al. “Ketogenic Diets and Chronic Disease: Weighing the Benefits Against the Risks. Frontiers in Nutrition, National Library of Medicine, 2021.
  5. Oh et al.Low Carbohydrate Diet.” StatPearls, National Library of Medicine, 2021.
  6. Scardina et al. “Good oral health and diet.” Journal of Biomedicine & Biotechnology, National Library of Medicine, 2012.
  7. Bostock et al. “Consumer Reports of ‘Keto Flu’ Associated With the Ketogenic Diet.” Frontiers in Nutrition, National Library of Medicine, 2020.
  8. Akkaoui S. & Ennibi O. “Use of traditional plants in management of halitosis in a Moroccan population.” J Intercult Ethnopharmacol, 2017.
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