Keto Breath: Why It Happens and How to Stop It

If you’ve recently embarked on a ketogenic diet, you may notice something other than the weight loss you were hoping for. Shortly after entering ketosis, your breath can start smelling different. You may even develop an odd, metallic taste. 'Keto breath' is a common side effect of eating a high-fat, low-carb diet. But there is good news. This pesky problem is usually temporary. So, let’s find out what causes keto breath in the first place and go over some tips for getting rid of this annoying and embarrassing problem.

What is keto breath?

Keto breath is actually a good sign for a ketogenic diet. In a typical American diet, your body uses carbs for energy. But with a low-carb diet, the body must switch its energy source to fats.


When fat is broken down for energy, it produces compounds called ketones. Excess ketones are excreted through urine, sweat, and exhalation. Therefore, keto breath is one sign your body has used up any stored carbs and has reached the state of ketosis.

What does keto breath smell like?

Keto breath can take on several different smells. Some people often describe it as sweet and fruity, similar to overripe fruit, while others state it takes on a fingernail polish remover smell. Both could be an indicator of ketosis. You can also experience a bitter, metallic taste in your mouth too. No matter what it smells like, it means your body is converting to using fats for energy instead of carbohydrates.

Causes of keto breath

Keto breath is usually a temporary side effect of the body entering ketosis. Your body is adjusting to a lower carb intake and switching energy sources to fat. When fat is broken down under low carbohydrate conditions, it becomes ketones. Over time, the body becomes more efficient at ketosis, and keto breath starts to go away.

Tips to get rid of keto breath

Keto breath is most noticeable in the first couple of weeks after ketosis begins. It usually disappears as the body begins to adjust to lower carbs and is more efficient at processing fats for energy. However, keto breath can be embarrassing and hard to deal with. Here are a few tips to help lessen keto breath:

Stay hydrated


Dehydration is common during ketosis. Therefore, keto breath is more noticeable and can last longer if you are not drinking enough water. Drinking plenty of water to keep your body hydrated may help to remove excess ketones from your system.

Maintain oral hygiene

Proper hygiene is crucial to preventing bad breath. Protein often becomes a source of volatile sulfur compounds (VSCs) in the mouth. Therefore, make sure you brush your teeth two times daily and floss or use a water flosser once daily. This helps remove VSCs and prevent bad breath. Incorporating alcohol-free mouthwash into your oral care routine can also help.

Chew sugar-free gum or mints

Chewing gum or breath mints helps mask keto breath while your body adjusts to your new diet. Just be sure to stick with sugar-free versions. Sugar-free gum typically has only five calories and less than two grams of carbs per stick. Chewing gum can also help curb hunger cravings as well.

Use natural breath fresheners

There are many ways to naturally fight bad breath. Try these natural breath freshener options:

  • Mint leaves
  • Cloves
  • Fennel seeds
  • Parsley
  • Cinnamon in a drink
  • Lemon water

Simply chewing on these fresh herbs or adding spices to whatever you are drinking can help keep your breath smelling fresh while keeping you in ketosis.

Oil pulling


Oil pulling can help fight bad breath and improve oral health by removing plaque and bacteria from your mouth. It does not replace the need for brushing and flossing, though. It simply helps reduce VSCs and other bacterial metabolism products that build up in the mouth to help freshen breath.

Adjust your diet

When you are early in your keto journey, it is common to overeat protein. So, as your body is adapting to a keto diet, slightly lowering your protein intake can help make keto breath less noticeable. Proteins are a source of VSC, which often cause your breath to smell bad. You may also consider adding ketone drinks to help your body make the transition into ketosis easier.

Give it time

Keto breath is a sign your body is entering ketosis. It is transitioning from using glucose for energy to using fat. This process is called keto adaptation and may take a few weeks for your body to completely adapt. As you stay in ketosis, ketone processing becomes more efficient, and keto breath should start fading.

Is keto breath harmful to your oral health?

Keto breath may be completely harmless side effect of the keto diet. However, keto breath with other symptoms may indicate a more serious medical problem. You should discontinue a keto diet if you begin to experience symptoms like:

  • Nausea
  • Excessive urination
  • Extreme weakness
  • Tiredness
  • Notable confusion

Also, someone with cardiovascular disease or those who have risk factors for CVD should avoid a keto diet due to its high lipid content. So, you should always consult your doctor to discuss the benefits and risks before starting a ketogenic diet. If keto isn't right for you, your doctor can help you find a more suitable diet that fits your needs.

While keto breath can be unpleasant and embarrassing, it is actually a sign that your body is adapting to using fat for fuel. Many people report experiencing keto breath by day 4 of a strict keto diet. This is usually when the body is starting to transition into ketosis. This can be a push to keep going on a keto diet and allow your body to completely enter keto adaptation.

A keto diet may be the key to a healthier lifestyle for you. And remember, although keto breath can be quite annoying, it does mean you are entering ketosis. Drink lots of water, maintain good oral health, and stay committed to your new lifestyle changes. Soon, you will be keto-adapted and enjoy the benefits of a low-carb lifestyle.



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