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What Breaks A Fast? The Truth About Food, Drink, And Meds

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What Breaks A Fast? The Truth About Food, Drink, And Meds

Hey there, fasting friend. So you’ve decided to give food fasting a try. You’re excited about the potential health benefits, like weight loss, improved insulin sensitivity, and increased longevity. But you have questions about what’s allowed and not allowed during your fast. Can you drink coffee? Take supplements? Have a splash of milk in your tea? Relax, we’ve got you covered. We’ll walk you through what breaks a fast and doesn’t so you can fast confidently. Whether you’re doing intermittent fasting, alternate day fasting, or extended fasts, use this guide to navigate the ins and outs of fasting and stay in a fasted state. By the end, you’ll be a fasting pro, reaping all the rewards that come with it.

What Breaks A Fast? The Truth About Food, Drink, And Meds

Food and Drinks That Break Your Fast

We all know eating or drinking breaks a food fast, but what exactly counts? It’s not as simple as you might think. Some things you consume actually don’t break your fast, while others definitely do.

Foods like fruits, vegetables, grains, and legumes contain calories and will break your fast. The same goes for dairy, meat, and nuts. Basically, if it has a significant amount of macronutrients like carbs, protein, or fat, it will interrupt your fast.

Beverages with calories such as juice, milk, and smoothies will also break your fast. However, black coffee, unsweetened tea, and water will not. They have virtually no calories so your body remains in a fasted state.

Broths and bone broths are iffy. While they typically only have around 50 calories per cup, they contain protein and nutrients. To be safe, avoid them if you want to stay in a completely fast state.

Sugar-free gum and mints are okay in moderation since they have little to no effect on your insulin levels or calorie intake. However, too much artificial sweetener may trigger an insulin response in some people.

As for supplements, fat-soluble vitamins like vitamins D, E, and K are best taken with food since they require fat for absorption. Water-soluble vitamins such as vitamins C and B vitamins are fine to take on an empty stomach and won’t break your fast.

The key is to avoid anything that significantly impacts your insulin, blood sugar or provides calories. If you stick to non-caloric beverages and avoid food, you’ll remain in a fasted state and continue reaping the benefits. The moment you consume more than approximately 50 calories, your body shifts into a fed state, and your fast is broken.

Certain Types of Medications and Supplements Break a Fast

Certain medications and supplements can disrupt your fast. While water, unsweetened beverages, and black coffee or tea are typically fine, anything with calories will break your fast.

Prescription Medications

If you take any prescription meds, check with your doctor before fasting to see if the timing or dosage needs adjustment. Some meds are best taken with food, while others may be less effective if taken during a fast.

Over-the-Counter Drugs

Most OTC drugs like ibuprofen or acetaminophen are fine to take during a fast, but liquid gels, syrups, or anything sweetened can break your fast. Stick to pill forms and avoid anything with artificial colors or sweeteners.


Most supplements will break a fast, including:

  • Protein powders: Contain amino acids and calories.
  • BCAAs: Branched-chain amino acids provide nutrients.
  • Fat burners: Often contain calories and stimulants.
  • Pre-workouts: Usually packed with calories, carbs, and amino acids.
  • Multivitamins: While important for health, most contain extra ingredients that disrupt fasting.

The only supplements considered fast-friendly are plain electrolyte tablets or powders with no sweeteners and unflavored fiber supplements.

The bottom line is if it has calories, artificial or natural sweeteners, or provides nutrition in any form, it will likely break your fast. Stick to water, unsweetened beverages, and black coffee or tea for the best fast results. Know what’s in anything you take and if in doubt, avoid it during your fast.

Artificial Sweeteners and Gum Break a Fast

Many people think that zero-calorie artificial sweeteners and sugar-free gum are okay during a fast because they don’t contain any calories. However, these can still break your fast.

Artificial sweeteners like aspartame, sucralose, saccharin, and stevia may be calorie-free, but they can still spike insulin levels and raise blood sugar. When you consume these sweeteners, your taste buds sense the sweet flavor and send signals to your brain that sugar is on the way. Your brain then triggers the release of insulin in anticipation of the sugar, which breaks your fast.

Sugar-free gum also contains artificial sweeteners that can stimulate an insulin response. In addition, the act of chewing gum awakens your digestive system and causes the release of stomach acid and enzymes, further breaking your fast.

While a piece of gum or a diet soda may seem harmless, consuming them during a fast can hinder the benefits. Some of these benefits include:

•Burning fat for fuel: When insulin is released, your body switches to burning carbs for energy instead of fat.

•Autophagy: The cellular recycling process triggered during long fasts is disrupted by sweeteners and the chewing action.

•Reduced inflammation: Insulin spikes can cause inflammation in the body, counteracting the anti-inflammatory effects of fasting.

•Gut rest: Your digestive tract gets a break from digestion during a fast but is awakened by sweeteners and chewing gum.

For the best results from your fasts, avoid all sweeteners and gum. Stick to plain water, black coffee, and unsweetened beverages. This will keep your body in the fasted state so you can reap all the benefits that food fasting has to offer. Stay strong—every little bite or sip counts!

Does Brushing Your Teeth Break a Fast? The Surprising Truth

Brushing your teeth is an important part of your daily hygiene routine, but does it break your fast? The short answer is no, brushing and flossing your teeth will not break your fast.

Your fast is broken when you consume calories, which activate your digestive system and metabolism. Brushing your teeth does not provide any calories, so your body remains in a fast state. However, some toothpaste and mouthwashes do contain artificial sweeteners, flavorings, and preservatives which some people prefer to avoid while fasting. If this is a concern for you, choose an all-natural toothpaste without any added sugars or chemicals.

What about the taste of toothpaste?

Some people worry that the taste of toothpaste in your mouth may trigger an insulin response or make you feel hungry, breaking your fast. There is no evidence that the taste of toothpaste alone causes an insulin spike or increases appetite hormones. As long as you are not swallowing the toothpaste, brushing should not impact your fasted state. Rinsing your mouth with water after brushing can help remove any remaining toothpaste residue and taste.

Does flossing break a fast?

Similar to brushing, flossing your teeth does not provide any calories so it will not break your fast. Flossing helps remove food particles and plaque between your teeth that a toothbrush can’t reach. It’s a good idea to floss at least once per day, especially when food-fasting, to promote good oral health.

In summary, keeping up with your regular oral hygiene routine during a fast will not break your fast or interrupt the benefits. Brush your teeth, floss, and use mouthwash as needed to keep your mouth clean and fresh. The most important thing is to avoid swallowing anything other than water. As long as you spit out all toothpaste, mouthwash, and any debris from flossing, you can maintain your fast and your bright smile!

Other Things That May Break Your Fast

While abstaining from food fasting and drinking is the main way to fast, you need to consider a few other things if you want to reap the benefits.


Supplement pills and powders can contain calories, so they may break your fast. Some supplements like BCAAs (branched chain amino acids) and whey protein provide protein that does have calories. It’s best to avoid taking anything with calories during your fast. However, non-caloric supplements like electrolyte tablets, multivitamins, and herbal supplements are fine and won’t break your fast.

Gum and Mints

Both gum and mints may contain artificial sweeteners or flavors that could trigger an insulin response, breaking your fast. It’s best to avoid chewing gum or sucking on mints while fasting. If you need to freshen your breath, try brushing your teeth or using mouthwash instead.


Black coffee, plain tea, and other unsweetened beverages are fine to consume during a fast and won’t break it. However, adding cream, milk, or sugar to your coffee or tea provides calories and will break your fast. The same goes for sweetened and flavored coffee and tea drinks. As with everything, consume caffeine in moderation. Too much can disrupt your sleep, stress your body, and become unhealthy.


Most medications will not break your fast, but some prescription and over-the-counter medicines need to be taken with food. Check with your doctor or pharmacist to see if any of your medications need to be taken with food. If so, you may need to adjust when you take them to fit your food fasting schedule.

By being mindful of these other potential fast-breaking factors, you can make sure you stay in a fasted state to gain all the benefits you’re looking for. Stick to only the essentials – water, black coffee, or plain tea – and avoid anything with calories during your fast. Before long, food fasting will become second nature.


So there you have it, the truth about what impacts your fast. As you can see, it’s not as simple as just avoiding food during your fast window. Many drinks and supplements can trigger an insulin response and metabolic changes that break your fast. The key is to stick to water, black coffee, and plain tea if you want to remain in a fasted state. Otherwise, even a splash of milk in your coffee or a few mints can kick you out of the fasted zone. The benefits of food fasting like fat burning and autophagy are maximized in a truly fasted state. So if you want to fast for health or weight loss, be diligent and avoid anything that stimulates your digestive system during your fast window. Stay hydrated, stick to the basics, and you’ll be burning fat in no time!

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