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What Breaks a Fast? Foods, Beverages, and Supplements


The question, “What breaks a fast?” is most relevant to beverages because fasting prohibits consuming anything with calories — and all foods contain calories. So, during fasting, you need to be careful about the things you’re drinking besides water unless you’re dry fasting.

In this article, you will learn what can break your fast, including how to break a fast with meals and supplements that support optimal health. But before that, here’s a short refresher on fasting.

What is Fasting?

Fasting is a lifestyle practice in which a person refrains from taking in calories within a specified period. The two major types of fasting are intermittent and prolonged. Intermittent fasting can last anywhere from 12-48 hours (with the 48-hour fast being an extended form) while prolonged fasting lasts more than 48 hours.

We’ve covered a lot of the benefits of intermittent fasting previously, such as increased fat loss and muscle preservation, improved blood sugar and insulin sensitivity, better outcomes in fatty liver disease, and reduced inflammation that’s linked to many chronic diseases (* , *).

People can choose from many different types of intermittent fasts — the 16:8 method being the most popular, where you forgo food and drinks with calories for 16 hours, then eat within 8 hours. More advanced fasts are the alternate-day fast where you switch between full fasting and eating days, and the one-meal-a-day or OMAD where you restrict your feeding window to 1 hour in a given day.

Then there’s the 5:2 diet, which is a modified fast that entails limiting your calorie intake to 500-600 kcal within 2 days, then eating normally for the remaining 5 days of the week. It leverages calorie restriction instead of a strict fast.

What Breaks a Fast?

Anything that contains calories can break a fast. This means that you are to avoid any kind of food, beverages, and supplements with calories.

It doesn’t matter if it’s ketogenic, paleo, vegan, carnivore, etc. because any amount of calories will provide your cells the energy they require. This may also result in the slight disruption of autophagy, the process of breaking down and recycling damaged cells — although calorie restriction alone (reducing your average daily calories) can also trigger the autophagy process (*).

But while consuming a few calories during your fasting window could slightly reduce autophagy, you’ll still remain in ketosis — the metabolic state where you’re burning your own stored body fat for energy. Other benefits of ketosis as a result of fasting (if not due to following a keto diet) are enhanced brain health and cognitive performance (* , *).

How Many Calories Break a Fast?

As you’ve learned, any calories will technically break a fast. With that in mind, you need to limit yourself to beverages that do not interfere with fasting. These include plain water, sparkling water, black coffee, tea, and calorie-free electrolytes.

  • Water: Plain or sparkling water is great for maintaining an intermittent fast. If you want something refreshing, you can squeeze juice from a lemon into a water pitcher, though note that each glass will probably have a very small number of calories.
  • Calorie-free electrolytes: While electrolytes are essential for energy production, they don’t contain any calories (except for electrolyte powders with calories from added sugars). During fasting, take a calorie-free electrolyte powder like Perfect Keto Daily Electrolytes to keep you hydrated, especially for a prolonged fast.
  • Black coffee or herbal tea: Many people who fast find that a cup of brewed coffee or herbal tea (without sweetener, cream, MCT oil, etc.) suppresses their appetite, making it easier to fast for longer periods (*). However, take note that coffee or tea has around 2 calories per cup. Proponents claim that these calories are negligible and do not impact fasting at all, while others state that this remains scientifically unproven.

Foods That Can Likely Break a Fast

As per the definition of fasting, it’s not recommended to eat during a fast, even with foods with very low calories, such as spinach and other leaf vegetables. So, what breaks your fast?

  • Meat
  • Seafood
  • Poultry
  • Eggs
  • Grains
  • Fruits
  • Vegetables
  • Nuts
  • Seeds
  • Snacks (whole or processed)

Beverages That Can Likely Break a Fast

Drinks that contain calories and are high in carbohydrates — like fruit juices and regular soda — not only break the fasting process, but they cause your blood sugar levels to rise fast and kick you out of ketosis. Therefore, be sure to avoid the following:

  • Coffee or tea with creamer, sugar, MCT oil
  • Bone broth
  • Smoothies
  • Juices
  • Coconut water
  • Milk, both dairy and non-dairy
  • Soda, both regular or sugar-free (some sweeteners in diet soda may cause an insulin spike)

Supplements That Can Likely Break a Fast

When it comes to supplementation, note that nutrients in their pure forms — such as vitamins and minerals — are calorie-free, which means that they won’t interfere with fasting. On the contrary, stay away from supplements with added sugar and other ingredients.

Supplements that will likely break your fast include:

  • Gummy vitamins
  • Chewable tablets
  • BCAAs or branched-chain amino acids as research shows BCAAs may cause an insulin response (*)
  • Whey, egg white, pea, and other protein powders

Additionally, keep in mind that certain supplements are best consumed with food for optimal absorption. For example, the fat-soluble vitamins A, D, E, and K require dietary fat so they can be properly absorbed. Therefore, it would be best to take them after fasting, with a meal that includes eggs and meat (*).

Omega-3 supplements are also to be avoided. Fish oil and cod liver oil capsules are pure fat, which means they contain calories.

What to Eat When Fasting

Breaking a fast already? In that case, we recommend focusing on foods that are nutrient-dense and satiating. Here’s a list of foods to eat during your feeding window:

Animal foods like beef, pork, eggs, poultry, and fatty fish are carbohydrate-free, plus they’re absorbed more easily and are complete sources of protein (*).

Nuts, cauliflower, broccoli, brussels sprouts, and other green above-ground vegetables are wonderful. Just know that cooked veggies are better than raw ones. Raw, fibrous vegetables are more difficult to digest.

Bone broth has a soothing effect on the gut and it’s full of health-boosting nutrients, including calcium, potassium, phosphorus, iron, zinc, and collagen. Make bone broth by simmering beef bones. You may also use bones from any animal, such as chicken, lamb, and fish.

Fermented foods like kimchi, unsweetened yogurt, kefir, and sauerkraut increase the beneficial bacteria in your gut, which help with digestion (*).

Lastly, whey protein isolate is an excellent protein source if you prefer breaking your fast with a protein-rich beverage, and it’s very digestible. Furthermore, whey protein isolate is low in carbohydrates.

What to Eat to Break Your Fast

Learning how to break a fast is also important, in addition to keeping yourself in a fasted state. Since you’re fasting for weight loss, better health, and longevity — it’s important to make sure that what you eat outside your fasting window will support these benefits.

That said, begin your feeding window with foods and drinks with fewer carbohydrates to avoid blood sugar spikes. Unprocessed meats and cooked non-starchy veggies are great options. The fact that low-carb foods support healthy blood sugar levels is one of the reasons why the keto diet and intermittent fasting are a great combination.

If you’re not following a keto diet, choose foods with a low glycemic index (GI). Examples of lower GI foods that aren’t necessarily “keto” include whole-grain bread and boiled sweet potatoes. Generally speaking, processed foods have a higher glycemic index, so stay away from potato chips, ice cream, cakes, and breakfast cereals.

In addition to high-carb and high-GI foods, steer clear of spicy foods post-fasting. That means reducing the amount of red pepper and chili flakes in kimchi and sauerkraut for those who opt to break their fast with these fermented options.

And last but not least, start with a smaller meal and eat slowly. It’s tempting to gorge on a supersized meal, especially if you feel very hungry. However, this may lead to bloating, gas, nausea, and diarrhea — even if it’s a healthy meal. (To reduce the likelihood of experiencing these symptoms post-fasting, some would recommend doing a shorter fast.)

The Bottom Line

The most effective approach to avoid breaking a fast is to stay away from anything you know contains calories. Plain water is best, but if you would like something else that prevents hunger, black coffee or unsweetened tea should be fine.

While this requires further proof, most people who fast agree that these options don’t affect fasting, and most especially ketosis. Just make sure to not add anything to coffee or tea.

Ending your fast doesn’t have to be complicated! Consume whole nutrient-dense, keto-friendly, low-GI foods, and avoid raw fibrous veggies as well as spicy foods. Following these tips will help you reap the health and weight loss benefits you seek from fasting.

10 References

Varkaneh H et al. Effects of the 5:2 intermittent fasting diet on non-alcoholic fatty liver disease: A randomized controlled trial. 2022 July 61

Jordan S et al. Dietary Intake Regulates the Circulating Inflammatory Monocyte Pool. 2019 August 22

Bagherniya M et al. The effect of fasting or calorie restriction on autophagy induction: A review of the literature. 2018 November

Charlie Foundation. Am I a Candidate? – Studies Show Efficacy of Keto for Brain Health.

Myette-Côté E et al. Ketones: potential to achieve brain energy rescue and sustain cognitive health during ageing. 2021 September 28

Schubert M et al. Caffeine, coffee, and appetite control: a review. 2017 April 27

Asghari G et al. High dietary intake of branched-chain amino acids is associated with an increased risk of insulin resistance in adults. 2018 February 9

Albahrani A et al. Fat-Soluble Vitamins: Clinical Indications and Current Challenges for Chromatographic Measurement. 2016 February

Reid-McCann R et al. The effect of animal versus plant protein on muscle mass, muscle strength, physical performance and sarcopenia in adults: protocol for a systematic review. 2022 April 13

Leeuwendaal N et al. Fermented Foods, Health and the Gut Microbiome. 2022 April 6


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