Does Pre-Workout Break A Fast? Ingredients To Avoid

Updated on  February 26, 2023
William Toro

Published By:  William Toro

Fact Checked by: Bridget MacDonald, RDN

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Everyone wants to see fast results when it comes to health and fitness. Fasting, especially intermittent fasting, has been researched [1] in the health and fitness industry to produce great results by boosting your metabolism and increasing fat oxidation.

Along with intermittent fasting, exercising is also necessary to achieve fitness goals. But fasting periods, in which you are not allowed to eat food, can last for several hours, causing your workout routine to slow down. Hence it raises the question if a pre-workout supplement breaks fast or not. This article discusses intermittent fasting and provides an answer to does pre-workout break a fast or not.

What Is Intermittent Fasting?


The concept of fasting has been around for many years. It is an excellent method to control eating patterns, burn fat [2], reach health and fitness goals quickly, and reduce the risk of specific health problems [3]. An effective fasting technique for maintaining body composition which you would often find a certified medical professional or a personal trainer recommending is intermittent fasting.

The intermittent fasting regimen includes an eating window that allows you to eat meals for a set amount of hours. This window is followed by a period of fasting that restricts eating food but allows you to intake water and other calorie-free fluids.  

For learning more about how intermittent fasting works, watch a video here: 

In order to achieve speedy results, intermittent fasting protocols state to avoid consuming food and beverages that are high in calories. Multiple types of intermittent fasting regimens exist that involve different ranges of eating and fasting windows, for example:

  • Fasting for sixteen hours with an eight-hour eating window.
  • Fasting for twenty hours with four hours of eating window
  • Fasting for twenty-four hours, two days a week. And eating normally during the rest of the five days of the week.

Since you might experience a lack of energy during intermittent fasting, it will be difficult to adjust any workout without a pre-workout supplement. Therefore, it is essential to know if pre-workouts break intermittent fasting or not. But before we get into it, let us see what everyday foods can break your fast.

Everyday Foods That Break Your Fast

Some foods that will break or affect your state of intermittent fasting include: [4]

  • Anything that contains even a tiny amount of calories, including a handful of crisps, low-calorie biscuits, or a tiny teaspoon of regular table sugar.
  • Sugary drinks like fizzy drinks, energy drinks, and organic or store-bought juices.
  • Any fruits and vegetables.

The main idea behind intermittent fasting is to abstain from eating, and hence that should be kept in mind while starting your new routine.

Although the food intake is limited for several hours, you can consume calorie-free fluids, as discussed later, to avoid disrupting the fasting window. These fluids can include water to stay hydrated throughout the day, black coffee without sweeteners and creamers, green tea, etc.

Can A Pre-Workout Break Your Fast?

Pre-workout supplements are taken before a workout to receive an additional boost of energy for better exercise performance. To make your exercise session effective, pre-workout supplements provide fitness benefits [7] like improving muscle condition, burning fat, enhancing mental focus, etc.

Whether a pre-workout breaks a fast or not depends entirely on the ingredients [4] and how many calories they contain. Some pre-workout ingredients can break fasts, while others do not interrupt the fasting period.

For enhancing taste, many pre-workout supplements contain sweeteners and flavorings that increase their calorific value. You should avoid such pre-workouts to prevent calorie intake during intermittent fasting and a rise in insulin levels. Moreover, although artificial sweeteners are zero-calorie, some might contribute to raising insulin response [8] and activating the digestive system. Hence, it is better to avoid any pre-workout blend that might contain natural and artificial sweeteners to maintain improved insulin sensitivity.

Carbohydrates like maltodextrin can break fast by increasing blood sugar [9] and calories to provide energy during workouts. Natural pre-workout ingredients like whey protein also technically break a fast as they contain calories.

Amino acids are necessary for building lean muscle mass. However, a proteinogenic amino acid containing pre-workout supplements breaks your fast by increasing calories, spiking insulin levels, and triggering the insulin response. Therefore, when intermittent fasting, it is better to not consume a pre-workout supplementation with proteinogenic amino acids like branched chain amino acids, glutamine, etc. [10]

While some fitness enthusiasts may argue that anything below 40 calories is safe to consume, the better option is to select a pre-workout with zero calories while following an intermittent fasting regimen.


Pre-Workout Supplement Ingredients For Intermittent Fasting 

1. Pre Lab Pro - Best Pre Workout for Fasting

next gen pre lab pro

Next Gen Prelab Pro

Form: Powder

Number of capsules: 60

How to use: 30 mins before Workout

Diet type: Doesn't Breaks Fast

During days of intermittent fasting, maintaining your workout performance is essential to achieving fitness goals. For good athletic performance and stable energy levels during fasting, taking a pre-workout supplement would deliver instant results.

As mentioned earlier, some pre-workout ingredients can technically break your fast. But there are other various ingredients that do not alter the fasting state and provide reasonable energy levels for daily exercise performance.

Compared to water-based, Pill-type pre-workouts are great for zero-calorie energy as they contain only active ingredients and no artificial sweeteners or flavorings. Best pre-workout supplements that are compatible with intermittent fasting protocols include ingredients like:


Caffeine is one of the most common ingredients added in pre-workout supplements. The caffeine used in most pre-workouts is extracted from natural ingredients like green coffee beans and green tea extracts. Some pre-workouts might contain caffeine anhydrous or other forms. Taking caffeine during intermittent fasting delivers several health benefits [11] like increased energy levels, decreased appetite, better endurance, etc., without raising insulin response and calorie intake. To learn more about the benefits of added caffeine in pre-workout supplements, watch a video here:


Can creatine break a fast even though it is an amino acid? Generally speaking, non-proteinogenic amino acids like creatine do not break a fast as they are calorie-free and do not spike insulin levels. Consuming a pre-workout with creatine is an excellent way to maintain energy levels during your exercise session by not altering your fasting state. It can also be a good alternative to proteinogenic amino acids for conserving muscle tissues and promoting muscle endurance [12]. You can check out some creatine-containing pre-workout supplements recommended by us.

Citrulline Malate

Citrulline malate is a vasodilator added to many pre-workout supplements to increase nitric oxide levels and muscle endurance and promote muscle growth [5]. It increases the diameter of blood vessels, which results in faster blood flow to muscle tissues, hence increasing the transport of oxygen and nutrients. Citrulline malate in pre-workouts does not break a fast and provides energy and supports lean muscle mass without increasing calories or insulin response.


Beta-alanine is another non-proteinogenic amino acid [6] that does not break a fast when consumed in pre-workouts. It acts as a pH buffer for muscles during challenging workouts and promotes muscle growth and strength without raising insulin levels. The effect of beta-alanine is felt through a tingling sensation, and it maintains energy levels by not altering your intermittent fasting state. If you do not like the tingling sensation beta-alanine causes, you can check out some beta-alanine-free pre-workout recommendations by us.

Natural Pre-Workout Alternatives For Intermittent Fasting

While many pre-workout supplement companies offer zero-calorie formulations, opting for natural ingredients can provide clean energy and not break your fast. These can include:

Black Coffee

A simple cup of black coffee can work as an excellent fat burner while increasing overall athletic performance, and it does not break your fast. Its caffeine content increases energy levels, decreases appetite, and works to burn fat [13]. Black coffee is also keto diet-friendly, preventing calories and insulin rise in the body.

Green Tea

Unsweetened green tea is another excellent option to feel energetic on days of intermittent fasting. It can be a good caffeine alternative for people who do not like the taste of black coffee and does not break your fast. Green tea [15] hydrates and refreshes the body and delivers energy for daily workout routines. Its antioxidant properties work as an excellent fat burner and maintain alertness for staying active.

Lemon Water

While searching for natural pre-workouts, you might ask: does drinking lemon water break a fast? The answer is no; it does not break your fast. Lemon water does not contain any calories and is a perfect drink to keep the body hydrated. Consuming lemon water [14] before or after workouts can help replenish electrolytes lost through sweating. However, it does not provide energy for a workout routine but is excellent for fat metabolism and keeping the body active throughout the entire day.


Fasting is a proven effective method [1] for improving body composition while providing health benefits. Opting for intermittent fasting and combining the routine with daily workouts is a healthier option to lose weight than consuming synthetic fat burners.

But to have a successful exercise routine while fasting, pre-workout supplements and natural alternatives can help you stay energetic. However, it is crucial to know that high-calorie pre-workout breaks your fast and contains ingredients like amino acids, carbohydrates, artificial sweeteners, flavorings, etc. Therefore, for pre-workout intermittent fasting, you should avoid such pre-workouts and select calorie-free ingredients like creatine, caffeine, beta-alanine, citrulline malate, etc.

William Toro

William Toro ‧ CPT & Nutritionist

William is a certified personal trainer from NASM, he has also been a rehab physiologist for sports persons. He has more than 15 years of experience training people. And has featured in multiple publications like FoxNews, CNBC, Bustle, and other. 

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