Does pre workout break a fast? Can you take it while fasting?

Introduction- Does pre workout break a fast?

If you are into working out and bodybuilding you must have heard about pre workout at least once. When it comes to fitness supplements, pre workout supplements are one of the most popular and best-selling supplements.

Along with pre workout supplements, another term called intermittent fasting has been gaining a lot of popularity in recent years.

Intermittent fasting is an eating plan that switches and alternates between periods of fasting and eating. It can help with weight loss and has many health benefits. Because of this, a lot of people have started fasting.

If you workout along with fasting many questions you might be wondering Does pre workout break a fast? Can you take pre workout while fasting? In this blog post, we will answer these questions and tell you if you should take a pre workout while fasting.

What is pre workout?

A pre workout is a fitness supplement that is taken about 30 to 60 minutes before working out to improve and boost workout performance. It is generally in powdered form which you have to mix with water and drink before working out [1].

This supplement increases your energy levels, endurance, and strength so that you can perform better than usual. It can do so with help of some of the common ingredients in pre workouts like Caffeine, beta-alanine, Branched – Chain amino acids (BCAAs), Creatine, and Green tea extract  [1, 2, 3].

Along with its immense benefits, an overdose of pre workout can lead to some side effects like increased blood pressure and heart rate, nausea, diarrhea, and vomiting [4].

What is fasting?

Simply, Fasting means a period of time where you stop eating and drinking mostly for health and religious factors. There are different types of fasting, but one of the most popular ones is intermittent fasting.

There are several types of intermittent fasting as well. The most popular one is when you fast for more than 12 hours a day and eat for the rest of the hours.

A known example includes the 16/8 method. In this, you have to fast 16 hours in a day and eat for the rest of 8 hours.

There are many benefits of intermittent fasting, some include- weight loss, increase in physical performance, help with diabetes and obesity-related problems, improves heart health, etc.

But mostly, intermittent fasting is done for the treatment of obesity. And intermittent fasting also shows some promise in treating obesity [5].

How does pre workout break your fast?

does pre workout break a fast
Image- skynesher/iStock

Pre workout supplements that contain calories can break a fast, as they trigger an insulin response and interrupt the fasting state. It’s important to read labels carefully and choose supplements that are in line with your fasting goals.

Well, the answer simply might lie in the ingredients of your pre workout but it is not solely dependent on the ingredients for example in some fasts you are allowed to eat for a certain time or certain types of food but in the other type if you consume anything the fast is broken. So, it might also depend on what type of fast you are doing.

But in general, the ingredients that are in the pre workout supplements contain calories that may break your fast. So let’s take a look at which ingredients might break your fast and which won’t.

Related: Does Creatine Break A Fast? Unlocking The Truth

Ingredients that break your fast

Pre workout and other supplement

Sugar, artificial sweeteners added flavors and Carbs

Almost every pre workout excluding some contains sugar, sweeteners, and other carbohydrates. The companies add these so that their pre workout tastes better and upgrades the product overall. 

These sugars and carbs contain calories that break your fast and they might even cause a spike in insulin levels which can then stop you from losing weight as well. 

Although a study states that few sweeteners may not affect insulin levels. But, you should still check if your pre workout contains sugar, artificial sweeteners, and other carbs and avoid them in order to make the most out of your fast. 

Amino Acids

Pre workout contains amino acids and amino acids also have some calories. 

As mentioned above Branched Chain Amino Acids (BCAAs) is one of the most common ingredients in pre workouts and research state that every 10 gram of BCAAs would have approximately 40 calories.

Moreover, just like sugars and sweeteners, BCAAs are also sometimes reported to cause spikes in insulin levels.

So, any pre workout containing amino acids will also break your fast.

Whey Proteins

We all know protein contains calories so pre workout containing protein might also break your fast.

Well if your pre workout contains any of the above substances then you have a chance for your fast to be broken. So, we highly suggest you check all the ingredients and substances included in your pre workout before you decide to use them or not while fasting.

Also Read: Pre Workout vs Fat Burner – Differences and Which Is Better?

Ingredients that won’t break your fast


Caffeine is one of the main ingredients in pre workout supplements. Consuming caffeine has a lot of benefits. Some benefits include increased energy levels, boosts metabolism, improves physical performance, enhanced muscle endurance, etc.

Furthermore, caffeine contains very little and almost no amount of calories so it won’t break your fast. 

It is also important that you don’t consume more than the required amount of caffeine especially when fasting, otherwise, it can have some potential side effects.


Creatine is a compound that is naturally found in your muscle cells.

Creatine can provide many benefits to you from muscle growth to increased strength, and energy levels, improved physical performance, can help in lowering blood sugar levels, etc.

A normal scoop of 5gm creatine does not contain any calories so consuming creatine will mostly not break your fast.

Citrulline Malate

Citrulline Malate refers to the blend of citrulline and another compound called malate.

It contains very few calories that might not break your fast and it has a lot of benefits as well like enhanced physical exercise, improved athletic performance, helps with erectile dysfunction, lowers blood pressure, etc.


Beta-alanine is a non-essential amino acid that is naturally produced by your body. Beta-alanine helps in the production of carnosine which can help in increasing muscle endurance.

Beta-alanine contains very few, almost no calories and also helps in reducing post workout fatigue. 

These are some main ingredients that will break or will not break your fast. You should keep in mind that your pre workout might contain some other substances that are not listed above which might or might not break your fast.

The Bottom Line

There is no simple answer to the question: does pre workout break a fast and can you take it while fasting? 

Whether or not pre workout will break your fast depends on the ingredients, so we highly recommend you check the ingredient list and nutrition info before you use it.

Most pre workouts will contain ingredients that can break your fast so it can also be a good idea to just stay away from pre workout supplements during your fasting period.

In the end, it’s your personal choice and up to you if you want to use pre workout while fasting then make sure to check the ingredient list and then consume it.

More Pre-Workout Supplement Guides

Why Is Pre-Workout So Expensive? Pre-Workout Price Paradox

Can You Take Pre-Workout On An Empty Stomach? Boost Gains?

Expired Pre-Workout: Does Pre-Workout Go Bad?

Can You Mix Creatine With Pre-Workout? Is It Safe?

Pre Workout Crash – Why Does Pre Workout Make Me Tired?


  1. Harty PS, Zabriskie HA, Erickson JL, Molling PE, Kerksick CM, Jagim AR. Multi-ingredient pre-workout supplements, safety implications, and performance outcomes: a brief review. J Int Soc Sports Nutr. 2018 Aug 8;15(1):41. doi: 10.1186/s12970-018-0247-6. PMID: 30089501; PMCID: PMC6083567.
  2. Martinez N, Campbell B, Franek M, Buchanan L, Colquhoun R. The effect of acute pre-workout supplementation on power and strength performance. J Int Soc Sports Nutr. 2016 Jul 16;13:29. doi: 10.1186/s12970-016-0138-7. PMID: 27429596; PMCID: PMC4947244.
  3. Kaczka P, Batra A, Kubicka K, Maciejczyk M, Rzeszutko-Bełzowska A, Pezdan-Śliż I, Michałowska-Sawczyn M, Przydział M, Płonka A, Cięszczyk P, Humińska-Lisowska K, Zając T. Effects of Pre-Workout Multi-Ingredient Supplement on Anaerobic Performance: Randomized Double-Blind Crossover Study. Int J Environ Res Public Health. 2020 Nov 9;17(21):8262. doi: 10.3390/ijerph17218262. PMID: 33182295; PMCID: PMC7664913.
  4. Jagim AR, Camic CL, Harty PS. Common Habits, Adverse Events, and Opinions Regarding Pre-Workout Supplement Use Among Regular Consumers. Nutrients. 2019 Apr 16;11(4):855. doi: 10.3390/nu11040855. PMID: 31014016; PMCID: PMC6520716.
  5. Welton S, Minty R, O’Driscoll T, Willms H, Poirier D, Madden S, Kelly L. Intermittent fasting and weight loss: Systematic review. Can Fam Physician. 2020 Feb;66(2):117-125. PMID: 32060194; PMCID: PMC7021351.

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