Oral benefits of fasting
When I did my first 5-day water-only fasting, I noticed some surprising immediate side effects. My teeth felt much cleaner. I found myself brushing teeth once a day, usually before leaving the house in the morning.
Moreover, fasting has the ability to completely reset the palate. Over-consumption and unhealthy eating habits cause our taste buds to be less sensitive. When your taste buds expect over-processed, hyper-palatable foods, natural whole foods can’t compete.
Highly refined sugars found in most processed foods, for example, over-stimulate the taste buds to the point where the natural sugars in fruit no longer satisfy a sweet tooth. You could say it allows you to start with a “blank canvas of flavour”.
There are many proven benefits of fasting, and I think the dental aspects are rarely talked about.

Teeth after using plaque disclosing tablets, fasting day-2 (dark spots: enamel abrasions)
As tooth abrasion is increasingly becoming a problem, less frequent brushing and eating might have some protective impacts. Especially when the gums are already receded, the cervical part of the teeth often show a typical loss of hard-structure which then leads to increased sensitivity and increased risk of caries.
Fasting helps you to control calorie intake, blood sugar and body weight which is foundational for overall health. It also increases the activity of a metabolic process called autophagy, when the cells clear their excess, unused, or damaged structures. The long term accumulation of these by-products may be linked to chronic conditions.
Different fasting regimens are widely popular nowadays. There are longer, multiple-day versions, alternate days, and the one called intermittent fasting (IF). During IF you restrict the time window of eating during the day, hence the other name time-restricted feeding. IF may vary from 1-12 hours of eating, depending on your goals and lifestyle.
Intermittent fasting regimens are hypothesized to influence metabolic regulation via effects on circadian biology, the gut microbiome, and modifiable lifestyle behaviours, such as sleep.
I’ve been practicing IF for a while now and noticed some benefits to my oral health. The less often you eat, and the less you use your teeth, the less you have to clean them. Plaque and damage accumulation is decreasing and the oral microbiome is altered in a beneficial way.
The most extreme version of IF is called OMAD (One Meal A Day). During OMAD you eat just one big (or small) meal in about an hour or so. Then if you brush the teeth, theoretically, you are done for the next 23 hours. Some flossing, chewing gum, or probiotic mouth-rinse might be a good extra option in different part of the day.
Chewing food rapidly changes the oral microbiota, in ways that depend on the nutrients consumed. It increases the bacteria growth in the short term and may cause shifts in the composition (dysbiosis) long term. Dysbiosis of the oral microbiota plays a role in several common diseases like tooth decays, gum inflammation or bad breath (halitosis).
What you consume on a regular basis is a key determining factor in the mouth and the gut microbiome. The millions of bacteria ‘starve’ when you don’t eat and multiply exponentially when there is plaque (food) is present in the mouth.
There is limited research done about the relationships between fasting and oral health. I hope we will see more in the future.
A healthy diet and less frequent eating may help good microbes to populate and protect all surfaces.
You want the oral flora to form a robust complex ecosystem, so pathogenic dysbiosis and disease is not an option. This way your mouth feels good, tastes good and smells good and common problems are prevented.
Fasting seem to benefit the gums and teeth, whether you have gum disease, history of frequent decays, or halitosis. It’s happening not just through a healthier diet and lifestyle, but by positively effecting the oral and gut microbiome.
Tell us about your experiences in the comments below!
Further readings and references:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6528490/
https://www.annualreviews.org/doi/abs/10.1146/annurev-nutr-071816-064634
https://academic.oup.com/jcag/article/1/suppl_1/14/4916168
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0170437