Does Biting Nails Break Intermittent Fasting?

Written by Andrew Brewer. ⚕️Reviewed and fact checked by our medical team.

does biting nails break intermittent fasting

In high stress, the nails are often the first thing to go. Some people pick them, peeling off the layers to channel their stress and anxiety, while others bite them, spitting them out so as not to accidentally swallow the jagged piece of keratin. What happens if you do swallow your nail after biting it? Does that mean you’ve broken your fast?

The answer is no. Biting and swallowing your nails does not break your intermittent fasting, as long as you’re not swallowing them intentionally. It’s suggested that you need to eat 40-80 calories to break your fast officially, so while you may feel guilty about swallowing your nails, you are not breaking your intermittent fast.

Now, that’s not to say that you shouldn’t try to kick this nasty habit. While it may not break your fast, that doesn’t mean it’s good for you. Here are three reasons you should try to stop biting your nails for good.

Key Takeaways

  • Biting and swallowing your nails does not break your intermittent fasting, as long as you’re not doing it intentionally.
  • Biting your nails can introduce germs into your mouth, leading to infections such as gum infections, throat infections, and cold and flu viruses.
  • Biting your nails can cause dental problems such as weakened teeth, misalignment, and even TMJ and chronic headaches. Additionally, ingesting nail polish can cause toxic poisoning.
  • It’s best to avoid biting your nails altogether for the sake of your health.

Why Biting Nails is Bad for You

Many people bite their nails because they’re feeling something, and they have no other way to address it. It can be self-soothing, and while there are worse vices out there, it can also be harmful to your health.


Remember, everything you touch throughout the day has the potential to be introduced into your mouth, and that includes doorknobs, toilet handles, computer keyboards, other people, and so much more. Even if you wash your hands regularly, your nails can still be a catch-all for many germs.

The moment you put your fingers in your mouth, you’re introducing these infection-causing microparticles into your mouth, which can cause gum infections, throat infections, cold and flu viruses, and more. You can even get serious illnesses like hepatitis and warts after biting your nails. If you pick the skin around it, you’re giving a secondary entry point for germs. No one wants to be sick, so try hard to keep your fingers out of your mouth to give yourself the best shot.

Teeth Problems

Biting your nails can be bad for your teeth, causing pre-mature damage that can cause your teeth to weaken over time. They may go out of alignment or become misshapen if you regularly bite your nails and favor one side. Some doctors even think that biting your teeth opens the door to grinding your teeth and jaw clenching, which can cause TMJ, broken teeth, chronic headaches, and other long-term health issues.

Toxic Poisoning

Many people paint their nails to stop biting them; however, it’s rarely a foolproof method. Instead, you end up eating some of the nail polish, which is incredibly bad for your health. Regular nail polish and gel polish are pumped full of toxins and harmful chemicals. If you eat a lot, you could cause toxic poisoning. Even if you’re ingesting a little at a time, it isn’t good for you.

So Does Biting Nails Break Intermittent Fasting?

No, nail-biting does not break intermittent fasting, but it’s still best to avoid it. It’s a nasty habit, and your quality of health will improve when you stop.

Don’t forget to check our best fasting apps to make your intermittent fasting journey easier.


  • Does biting your nails break intermittent fasting?

No, biting your nails do not break intermittent fasting because it does not involve consuming food or beverages that contain calories.

  • What activities can break intermittent fasting?

Activities that involve the consumption of food or beverages that contain calories can break intermittent fasting. These include eating, drinking, and taking supplements that contain calories.

  • Can chewing gum break intermittent fasting?

Chewing gum can break intermittent fasting if the gum contains sugar or calories. However, sugar-free gum that does not contain calories is generally considered to be safe to consume during intermittent fasting.

  • Can using mouthwash break intermittent fasting?

Using mouthwash is generally considered safe during intermittent fasting because it does not involve consuming food or beverages that contain calories. However, some mouthwashes may contain small amounts of calories, so it is important to read the label carefully.

  • Does biting your nails have any other negative effects on your health?

Biting nails can lead to various negative health effects, including infections, nail and cuticle damage, and dental problems. It can also indicate anxiety or other underlying mental health issues.

Andrew Brewer

Andrew Brewer

Andrew Brewer started to give people the guidance that he never received when he was first starting. His goal is to make your goals achievable and to offer you only the best fasting apps that the internet has to offer. You're not on your own - Andrew and the entire family of reviewers at are here with you every step of the way!