The Lowdown on Keto Breath: A Dental Hygienist Weighs In


An aspect of being a dental hygienist is talking to people about their diet, what they consume, how frequently, and how their diet impacts their oral health and mouth. The ketogenic “keto” diet that has become more popular in recent years can affect the mouth and how our breath smells.

Ketosis caused by the ketogenic diet increases acetone production, which is then expelled through the breath and urine. Acetone breath can be fruity or sweet or take on a nail polish remover smell. It can be unpleasant and even cause a metallic taste in the mouth.

Bad breath or changes in breath can happen for many reasons, but following a strict keto diet can affect breath. Below I go into more detail about why bad breath occurs while following the keto diet, how to stop or reduce bad breath, and how long the bad breath will last while on the keto diet.

Why do you have bad breath on keto?

As a dental hygienist, bad breath is a topic that I get asked a lot of questions about and discuss with my patients.

Because the ketogenic diet is a high-fat, low-carbohydrate diet, it causes the body to burn fat for energy rather than carbohydrates.

The metabolic process of burning fat instead of carbohydrates induces ketosis (and why the diet is named keto).

Ketones are produced when fat is broken down including acetoacetic acid, beta-hydroxybutyric acid and acetone. SourceOpens in a new tab..

Acetone is the ketone responsible for the fruity, sweet, metallic or nail polish remover smell in the breath.

Not every person who follows the keto diet will develop bad breath, depending on how strictly they follow the diet, their genetic makeup, and their oral health status.

Read Now: Is Bad Breath Embarrassing? Signs, Causes and What to Do!

Just remember, keto breath is a normal occurrence and will not negatively affect your oral health.

However, bad breath can make you more self-conscious and can be unpleasant. If you are experiencing keto breath, below is how to stop and reduce it.

Goodbye keto breath: Tips and tricks from a Dental hygienist

Depending on a few different factors, it may be challenging to stop keto breath altogether, but below are all the ways you can combat it. It may reduce keto breath and reduce it enough that it is not noticeable any longer.

  1. Stay Hydrated

A dry mouth substantially increases bad breath by promoting bacterial growth and reproduction.

While on the keto diet, you may experience dry mouth because of the body’s fluid balance changes.

Staying hydrated is essential for keeping the mouth moist and helping to rinse away food debris, and preventing the oral microbiome from thriving too much.

Keep a water bottle near you to sip on throughout the day, and have water intake goals.

Drink lots of water after eating and even rinse your mouth out with water to help rinse away acid and food debris.

  1. Brush and Floss Regularly

Flossing and brushing are so important. We dental professionals can sound like a broken record when it comes to encouraging people to floss and brush, but it is honestly so important to our oral and total body health.

Did you know that the bacteria in the mouth contribute to gum disease and cavities? Gum disease and cavities can also contribute to bad breath!

Brush your teeth twice a day (morning and evening right before bed), and if you find that while you are on the keto diet, your breath has changed, you can even add in a brush during the day. Brushing three times a day is not always necessary. However, it can help to combat bad breath.

Floss once a day!

When you do not floss, you miss cleaning 35% of the tooth surface.

We joke around in the dental world that not flossing is like only wiping your bum cheeks after going number 2. I find this hilarious, even though it does not sound that pleasant. But not flossing is not nice either and can have detrimental effects on your oral health and body health.

Read Now: What Happens if You Never Floss? Dental Hygienist Explains!

Also, don’t forget to replace your brush every three to four months or after you have been ill.

Xylitol mints/lozenges/gum can help combat bad breath.
  1. Chew Sugar-Free Gum or Mints that contain xylitol

Always choose a gum or mint that contains xylitol.

Xylitol is the most mouth-friendly ingredient as it inhibits the growth of cavity-causing bacteria and stimulates the salivary glands to produce more saliva to help rinse bacteria and food debris and keep the mouth moist.

  1. Avoid Certain Foods and Drinks

High-fat foods, alcohol, coffee, garlic, onion, sticky/pasty foods, sugar (even natural), and acid contribute to bad breath.

Avoiding these foods and drinks may be difficult, but limiting the intake can help prevent bad breath.

  1. Visit Your Dental Hygienist Regularly

Regular dental hygiene appointments are essential for maintaining oral health and preventing bad breath.

Bad breath is not just from diet changes but also gum disease. During your dental hygiene appointment, we clean your teeth and check for gum disease and cavities and will discuss how to manage gum disease and prevent bad breath!

Read Now: How Dental Hygienists Clean Teeth! What You Need to Know!

  1. Be patient – it will go away as the body adjusts to low sugar

Preventing bad breath while on a ketogenic diet requires a well-rounded approach. It combines good oral hygiene practices, avoiding certain foods and drinks, visiting your dental hygienist regularly, and staying hydrated.

But please be patient. The keto breath will go away or become much less noticeable for most people as the body adjusts to low sugar.

If you're experiencing persistent bad breath, it's essential to see your dentist to rule out any underlying oral health issues. Again, discussing this with your dental professional is very important. 

How long does keto breath last on the keto diet?

As I just mentioned, the keto breath will slowly go away or become much less as time goes on and the body adjusts to being deprived of sugar.

How long keto breath lasts depends on how strict you are following the diet, the length of time on the ketogenic diet, and your body’s metabolism.

On average, the keto breath will last for three weeks after the keto diet starts. During the first three weeks of the diet, the body adjusts to burning fat instead of carbohydrates. After the body has fully adjusted, the keto breath will subside.

If the keto breath does not go away after three weeks into the diet and even continues for months, it may be a sign that your body is not in full ketosis, and the diet will need to be adjusted.


Remember, a healthy mouth contributes to a healthy body!

Keep smiling!

Holly 🙂

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