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Acetone Breath: What Causes It and Is It Dangerous?

By Fitoru | 18 September 2019
Curly haired woman smelled something stinky plugging her nose

Acetone breath, sometimes known as “keto breath” because it arises during the transition to the ketogenic diet, can be a very concerning experience. When you start breathing fumes that smell not unlike nail polish remover, you naturally worry that something’s gone wrong with your health, possibly your kidneys. In fact, for people with type 1 diabetes (less so type 2 diabetes), acetone breath could be an indication of diabetic ketoacidosis (DKA), which is a life-threatening emergency. This article explains the cause of acetone breath, when you should be concerned, and how to help cure it.

What Causes Acetone Breath?

Acetone breath occurs when your body is so full of the ketone bodies derived from fatty acids that they have to be expelled via exhalation. What causes an overabundance of ketone bodies? One of the most common causes is switching to the keto diet.

Common Cause: The Keto Diet

The keto diet is a high-fat, low-carb diet designed to switch the body’s metabolism from using sugar (blood glucose) for energy to using fat (blood ketones). This is the natural alternative metabolism known as ketosis that your body is built to access in times of famine—the fat stored on your body can be used as energy if you’re not eating enough to supply the body with fast-acting sugar energy. 

Ketogenic meals reduce carb and sugar intake and increase healthy fat consumption to achieve fast yet safe weight loss thanks to ketosis. One temporary side effect of this changeover is that the body produces more ketones than it can process. Acetone is one of those ketones (along with beta hydroxybutyrate and acetoacetate). Therefore “keto breath” is one of the common symptoms of “keto flu.” In fact, keto dieters can use breath tests to measure their breath acetone concentration as a reliable indicator of ketosis.

Concerning Cause: Ketoacidosis

Acetone breath can also occur in people with diabetes mellitus, and in those cases it’s not a temporary side effect but a sign of extremely high blood sugar levels (hyperglycemia) that aren’t being processed, which is why the body has suddenly switched in a panic to accessing massive amounts of ketones for energy. Such a complication could lead to diabetic shock, coma, and even death if not treated quickly.

Long story short, while ketone levels in your urine and breath are not dangerous in and of themselves, it does matter what is causing them to be there. If you’ve just begun a low-carbohydrate diet for fat loss, you can monitor your urine or breath samples to make sure you’re getting into ketosis ASAP, and it’s a good thing. However, if you’re diabetic, any sign that your body isn’t interacting normally with your blood sugar levels is a medical emergency, and you should seek immediate professional care.

What Causes Acetone Breath?

How to Cure Acetone Breath on Keto

If your acetone breath is due to being on the keto diet, you don’t have to worry that your body’s in danger. In fact, keto breath is a sign that your diet is successfully taking effect, and soon you’ll be in ketosis and dropping weight like hotcakes.

However, that doesn’t mean that acetone breath is any more welcome than halitosis: it’s bad breath, it’s embarrassing, and it can cause a strangely fruity yet metallic taste that interrupts the enjoyment of your meals. We have some tips for oral health on keto that can help you manage keto breath and gently get to a state of ketosis so you’ll be beyond this transition phase and free of its side effects in no time.

Cover up Keto Breath with Gum, Mints, or Mouthwash

This is a crutch rather than a cure, but knowing that keto breath is a temporary side effect, you could just mask it for a week or two with strong gum, mints, or mouthwash in your desk drawer at work. Your only concern here is that you want to make sure you’re consuming sugar-free mints and gum, because even a little amount of sugar unaccounted for in keto can kick you out of ketosis or leave you in this keto flu phase for longer.

Drink More Water

If you’re suddenly so riddled with more ketones than your body can handle that you have to breathe them out, that means your body is also trying to clean them out through your urine. By drinking more water and urinating more often, you can give your body the means to filter out ketones instead of exhaling them into the faces of your family, friends, and coworkers. 

Not only does drinking more water help to flush out extra ketones, but it also keeps you hydrated and feeling fuller as you transition to a new diet. Studies show that drinking a glass of water before a meal significantly reduces calorie consumption by increasing satiation, making water consumption part of an effective weight-loss strategy.

Consume Less Protein

While the keto diet is mainly thought of as a high-fat and low-carb diet, it’s also a moderate-protein diet. “Moderate” means that about 20% of your daily calorie intake should be coming from protein, but because protein can contribute to bad breath, you may want to decrease your protein intake to 15% and up healthy fats like nuts and avocados in its place.

When the body metabolizes protein, the byproduct of that breakdown is ammonia, and it also leaves your body via urination and exhalation. Ammonia combined with acetone on your breath makes the whole concoction worse, so consider lowering your protein consumption until you’re safely stabilized in a state of ketosis.

Eat More Carbs and Wait Longer for Weight Loss

You may not like the sound of this, because you know that increasing your carbs could mean a delay in reaching ketosis. That is pretty much the point: by allowing your body access to just a little more carb energy while transitioning to ketosis, you can lessen the severity of keto flu symptoms. 

If the choice is between 1 week of withering breath and other keto flu symptoms like keto headache, or waiting 2 to 3 weeks to start dropping weight but without such an intense hazing-like process…maybe you’d prefer to wait? It’s really a matter of personal preference and taking a realistic measure of just how uncomfortable your keto flu symptoms are.

How to Own Acetone Breath

Turning your body into a fat-burning machine is a healthy way to prevent the development of metabolic disorders like obesity, high blood pressure, and type 2 diabetes. Our bodies are amazingly strong and adaptive, with two different ways to derive energy from our food. And the fact that science has revealed how to take control of our energy on such a cellular level is even more incredible. 

Acetone on your breath can be inconvenient and unwelcome, but it’s a small price to pay in comparison to the benefits of the keto diet.


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