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Home arrow Nutrition arrow Intermittent Fasting arrow Does Brushing Teeth Break a Fast? Everything You Need Know

Does Brushing Teeth Break a Fast? Everything You Need Know

Written by Edibel Quintero, RD
Fact checked by Rosmy Barrios, MD
Last update: January 3, 2024
6 min read 1481 Views 0 Comments
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Fasting facts: the surprising impact of dental hygiene on your facts

does brushing teeth break fast

Believe it or not, some debate whether brushing teeth breaks a fast. On one side of the argument, people say that since you technically ingest some of the toothpaste by drinking water, you are breaking your fast. 

On the other hand, people argue that as long as you don’t swallow the water or toothpaste, you’re still in the clear. So, who’s right?

The truth is, it depends on who you ask. There is no right or wrong answer, which ultimately comes down to personal preference. If you are someone who is strictly adhering to the rules of intermittent fasting, then you may want to avoid brushing your teeth altogether and have a toothpaste break. However, brushing your teeth won’t make a difference if you are more lenient with the rules.

In this article, we’ll explore the debate over whether brushing teeth breaks a fast and offer some tips for keeping your dental hygiene in check while fasting.

Does Brushing Teeth Break a Fast?

There is no solid reason to suggest that brushing teeth with toothpaste while fasting breaks a fast as long as you are not eating the toothpaste.

It is important to clean the mouth using a brush and a tooth stick. Many experts believe it is absolutely fine to brush one’s teeth during a fast. As you are cautious not to consume any of it, you can brush your teeth with toothpaste while fasting. 

The primary purpose of brushing your teeth is to remove any food remains to avoid tooth decay. Therefore, as long as you make sure to spit out all of the toothpaste after brushing, there is no risk of breaking your fast. 

What’s in a Toothpaste?

Toothpaste contains chemicals and ingredients that most don’t even know about. The current toothpaste market offers a wide variety of products. While each brand’s composition varies, most use the same primary ingredient. 

Let us explore the different ingredients found in toothpaste and what they do. 

#1 Fluoride

The primary cavity-prevention component of toothpaste is fluoride. Fluoride is present in every tube of toothpaste bearing the ADA certification. The mineral fluoride strengthens your tooth enamel, making it less prone to decay and less likely to wear away from acidic foods and beverages.

#2 Detergents

Other names for detergents include soaps, foaming agents, and surfactants. Chemicals with different characteristics, such as oil and water, are removed using detergents. To disguise their flavor when detergent is present, flavoring is needed. When you brush, detergents make your toothpaste foamy. 

Thanks to the foam, your teeth are coated with other active substances. The detergents’ foaming action also stops toothpaste from dropping out of the mouth as you brush.

#3 Flavor

Although they don’t taste good, fluoride and abrasives can help clean and protect your teeth. For better flavor, flavoring is added to toothpaste. Additionally, it hides the taste of detergent ingredients, particularly SLS. Because of this, flavorings are frequently found in toothpaste.

Often used flavorings include peppermint, cinnamon, wintergreen, spearmint, and menthol. While toothpaste with sweeteners may receive the ADA’s Seal of Acceptance, toothpaste with sugar will not be recommended.

#4 Abrasive

Abrasives are an active component of toothpaste, but because they don’t lower your risk of cavities or gum disease, they are considered inactive ingredients. Abrasives are crucial components, nevertheless, as they aid in cleaning off food particles and surface stains from teeth. 

Abrasives are what gives toothpaste its cleaning ability and are used to eliminate plaque and tartar. Abrasives also polish teeth and get rid of discolorations from the teeth.

Alumina, dicalcium phosphate, hydrated silica, calcium carbonate, and sodium bicarbonate (baking soda) are standard abrasives. These components clean and scrape the surface of your teeth without causing enamel damage or tooth decay. 

Notably, too abrasive toothpaste might erode tooth enamel and irritate the gum line. This may cause tooth sensitivity and tooth discoloration. To avoid damaging your teeth, be mindful of these abrasives and avoid applying excessive pressure with your toothbrush.

#5 Humectants and surfactants

The components known as humectants prevent your toothpaste from drying out and crumbling. The consistency of the paste-like texture and water retention in the toothpaste are achieved using humectants. Many natural brands are using coconut oil as the base.

Am I Allowed to Brush My Teeth While Fasting?

One common question is whether or not you’re allowed to brush your teeth while observing a fast. After all, water is involved, and you’re technically putting something in your mouth. However, the answer is a typical yes – you can brush your teeth while fasting.

Water is only used to help rinse away any food particles that may be stuck in your teeth when you eat, and it’s not considered part of the fasting process. 

So go ahead and brush your teeth as you usually would – just be sure to avoid any minty or sugary toothpaste that could trigger cravings. And if you’re still unsure, it’s always best to ask a professional and people with relevant experience before starting any new diet or fasting regimen.

If you don’t feel good about brushing your teeth while practicing intermittent fasting, you can try oil pulling with coconut oil as long as you are not swallowing it. Oil pulling is a common oral hygiene practice and might help prevent tooth decay and reduce bad bacteria in your mouth.

Does Mouthwash Break Intermittent Fasting?

The short answer is no – mouthwash does not break a fast. This is because mouthwash is not absorbed into the bloodstream like food and drinks are. Therefore, it will not impact the fast in any way. 

Using mouthwash during the intermittent fasting journey can be beneficial as it can help prevent bad breath and kill bacteria in the mouth. Just be sure to avoid mouthwashes containing sugar or other sweeteners, as these can trigger cravings and disrupt the fast.

For example, many types of mouthwash have ethanol, a variety of alcohol. When consumed, alcohol is broken down into sugar, which can then be used for energy. This means that if ingested, using mouthwash while fasting can potentially break the fast and cause your body to start burning sugar instead of fat. 

Even though mouthwash includes components that may cause all those effects if consumed, you won’t be drinking it. A fasting person ought to spit it out after using it to rinse their mouth. Yes, some taste will always be left over, and some little residue can lead to gum disease.

However, in theory, the small amount shouldn’t be sufficient to trigger an insulin response and cause your body to shift out of fat-burning mode. There won’t be much residue left, so a fast shouldn’t be broken. If you’re concerned, go a step further and use water to rinse your tongue and mouth.


Are you allowed to brush your teeth while fasting?

When fasting, you abstain from food and drink for a set period. This can be for religious or spiritual reasons, or it may be part of a health plan. You may still perform other activities during fasting, such as brushing your teeth. Brushing does not break your fast because you are not consuming any meal or drink. You can brush your teeth while fasting but do not use it as an excuse to ingest water or toothpaste.

Can you brush your teeth when fasting for a blood test?

Yes, you can brush your teeth when intermittent fasting for a blood test. Fasting for a blood test means abstaining from food and drink (except water) for a set period before the test. This is usually 8–12 hours.

Can we brush with toothpaste while fasting?

Brushing with toothpaste while intermittent fasting is fine, but avoid using mouthwash as it can contain alcohol or other ingredients that may break the fast. Spit out toothpaste after brushing, and rinse your mouth with water.

A Word From a Nutritionist

An intermittent fasting journey is a great way to cleanse your body and give your organs a break. When you fast, your body goes into a state of repair and detoxification, the so-called fat-burning mode. However, as advised, taking care of your oral health while fasting is important.

Brushing your teeth and using a toothpick before and after eating can help remove food particles and bacteria from your mouth, and it can also help freshen your breath, especially your morning breath.

Just be sure to avoid swallowing any water or toothpaste while brushing, and you’ll be able to keep your fast on track.

Following these simple guidelines can help you enjoy the benefits of intermittent fasting while keeping your oral health in top condition.


Some people find that brushing their teeth makes them feel like they’ve broken their fast and ruins the whole point of intermittent fasting. Others don’t mind a quick brush-and-swish before continuing with their day. 

It comes down to personal preference and what works best for you. If you brush your teeth during your fasting window, ensure you don’t intentionally ingest the toothpaste or water. Good oral hygiene is important, so make sure you use a toothpick as well.

Written by Edibel Quintero, RD
Edibel Quintero is a medical doctor who graduated in 2013 from the University of Zulia and has been working in her profession since then. She specializes in obesity and nutrition, physical rehabilitation, sports massage and post-operative rehabilitation. Edibel’s goal is to help people live healthier lives by educating them about food, exercise, mental wellness and other lifestyle choices that can improve their quality of life.
The article was fact checked by Rosmy Barrios, MD
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Written by Edibel Quintero, RD
Fact checked by Rosmy Barrios, MD
Last update: January 3, 2024
6 min read 1481 Views 0 Comments

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