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Does Pre-Workout Break a Fast?

Many people rely on pre-workout supplements for training purposes. It helps enhance performance during a workout by boosting energy levels, endurance, and focus. Afterward, it can aid the recovery process, easing the fatigue of high-intensity exercise.

If you’ve decided to try intermittent fasting, you will soon find that you must be mindful of what goes into your body. A fast means food abstinence, and while technically you shouldn’t consume anything, you may benefit from certain products.

In this article, find out all you need to know about pre-workout supplements and intermittent fasting.

What Is Pre-Workout?

Pre-workout is a generic term for pre-workout supplements in the health and fitness industry that athletes, weightlifters, and those in training use to enhance performance during workouts. They are often referred to as pre-workouts.

People tend to experience increased energy levels, greater mental focus, and improved muscle endurance after taking a pre-workout supplement.

These dietary formulas are rich with ingredients that increase blood flow and deliver essential nutrients to the muscles. Most pre-workout supplements come in powder form that you mix with water or another beverage of your choice and drink before exercise.

There are several health benefits of using a pre-workout alongside intermittent fasting. It can help boost your energy levels, enabling you to continue training without your usual fuel from food sources.

As the name suggests, you can take a pre-workout before you begin to exercise. It is crucial to select a calorie-free pre-workout if you are consuming it during the fasting window so that you don’t break your fast.

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Does Pre-Workout Break a Fast?

Whether your choice of pre-workout breaks a fast depends on the contents, as several specific ingredients will break your fast. It’s critical to recognize the elements to avoid, so you don’t hinder your efforts.

Pre-workout formulas differ between brands as there is no set list of ingredients. That said, many pre-workout supplements have common components as they all seek to deliver the same results. Quantities, quality, and purity of ingredients vary greatly.

Pre-workouts are essentially a blend of amino acids, vitamins, minerals, and artificial sweeteners. Popular ingredients for pre-workouts include caffeine, creatine, beta-alanine, and citrulline.

The idea is that these components support exercise performance and muscle growth and may even promote fat burning.

Intermittent fasting is a period where you don’t consume any calories. So, technically, any number of calories will break a fast.

Most pre-workouts have zero calories. Therefore, you can consume them without breaking your fast. However, many contain artificial sweeteners and sugar alcohols which may break a fast. Amino acids also have calories which will raise insulin levels.

As intermittent fasting is quite a transition from your usual eating pattern, you can benefit significantly from using the DoFasting app. The app is a tool designed to make fasting easier, with daily schedules, calorie tracking, guidance, and recipes to ensure a nutritious, fast-friendly diet.

3 ingredients to watch out for

There are three main ingredients found in pre-workouts that can break a fast. To prevent interrupting your fast, checking the label and avoiding the below pre-workout ingredients in your supplements is best.

1. Sugar, artificial sweeteners, and other carbohydrates

Many pre-workout supplements contain added sugar, artificial sweeteners, and carbs. Manufacturers add these ingredients to enhance the product’s taste without necessarily adding calories.

Most people choose to avoid these as they trigger an insulin spike, ending your fast. If you are fasting for weight loss, your goal will likely be to reach ketosis. Facilitating ketosis requires the depletion of glycogen stores so your body can tap into fat stores for energy instead.

Consuming sugar and carbs will kick you out of ketosis as your body breaks them down into glucose. This is why people following the keto diet limit carbohydrate intake.

2. Whey protein

Whey protein supplementation is popular for improving athletic performance, promoting lean muscle mass, and aiding muscle recovery. It may also aid weight loss by increasing your protein intake. For these reasons, it is a common ingredient in pre-workout supplements.

Whey protein breaks a fast because it contains enough calories to cause an insulin response. While you may benefit from protein supplements to reach your fitness goals, you should avoid them during the fasting period.

3. Amino acids

Amino acids are the building blocks of protein and are essential to a healthy diet. Manufacturers include amino acids in pre-workouts as they have many health benefits, like providing energy, building muscle, and repairing body tissue.

Unfortunately, amino acids, including branched-chain amino acids, naturally contain calories, protein, and carbohydrates that the body must metabolize and therefore interrupt the fasted state.

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4 Ingredients That Won’t Break a Fast

Although many pre-workouts contain the above ingredients, there are still plenty that won’t break your fast. In searching for a pre-workout supplement, look for the following natural ingredients.

1. Caffeine

Caffeine is a natural stimulant that increases activity in the brain and central nervous system. It is found in caffeinated drinks such as coffee, tea, and energy drinks. It’s also popular in pre-workout drinks as it can help you feel more awake, alert, and energized, enhancing exercise performance.

Further benefits of caffeine include:

2. Creatine

Creatine is a natural substance found primarily in the muscles. It fuels your muscles with energy during physical activity and is a beneficial ingredient in pre-workouts as it can help build muscle, strength, and athletic performance.


  • Creatine is highly effective for building muscle.
  • It is considered one of the most effective nutritional aids for athletes to improve high-intensity performance.
  • It may reduce fatigue.

3. Beta-alanine

Beta-alanine is a non-essential amino acid naturally produced by the human body. It works together with histidine to create carnosine—a building block of protein that is concentrated in the muscles. It is a common pre-workout supplement that aids exercise performance.

Additional benefits include:

  • Beta-alanine supplementation increases carnosine levels, providing antioxidant effects against oxidative stress.
  • It may improve exercise capacity and cognitive function in aging populations.

4. Citrulline malate

Citrulline malate is an amino acid that encourages the production of nitric oxide—a vital component for healthy blood vessels. You can find it in pre-workouts as it may enhance exercise and improve muscle recovery.

Citrulline malate also:

What Can You Use Instead of Pre-Workout During Intermittent Fasting?

Other drinks can support your exercise routine and boost your fitness journey if you decide against using a pre-workout blend during intermittent fasting. At the top of our list is coffee and green or matcha tea. Here’s why.


Coffee is high in caffeine—an effective stimulant that increases your energy, improves mood, and reduces fatigue. The beneficial effects of caffeine make coffee an established sports-performance aid.

As coffee has almost no calories, it is suitable to drink during fasting windows. Remember, we’re talking about black coffee. Adding ingredients such as milk, cream, and regular table sugar will render your cup of coffee no longer fast-friendly.

You should begin with a small dose of coffee as a pre-workout. No more than one or two cups before your workout should provide benefits without causing adverse effects.

Other perks of drinking coffee include:

  • Black coffee is extremely low in calories and can help you lose weight by suppressing appetite and curbing hunger.
  • It is a cheap alternative to branded pre-workout supplements.
  • Coffee has powerful antioxidant and anti-inflammatory properties that are beneficial to overall health. For example, coffee is associated with a reduced risk of colon cancer.
  • Consumption of coffee may reduce the risk of heart disease.
  • Both coffee and intermittent fasting are associated with reduced inflammation.

Green tea or matcha

Green tea or matcha are excellent pre-workout supplements. Both are natural, nutritious, and virtually calorie-free. Like coffee, they each contain caffeine, which can increase energy levels, supporting your fitness regimen.

Again, stick to one-two cups to prevent consuming too much caffeine and experiencing symptoms including jitters, fast heart rate, restlessness, and headaches.

Other benefits include:

What Else Breaks a Fast?

Generally speaking, consuming any number of calories breaks a fast. If you are following a strict intermittent fasting plan, you should refrain from all food and drinks containing calories. Even foods with just a few calories, such as berries, can break your fast.

However, there is some debate over how many calories actually hinder a fast. According to some methods, consuming less than 50 calories will not physically interrupt your fast or prevent the perks.

Many modified intermittent fasting methods even allow participants to consume up to 25% of their daily calorie needs during the fasting period.

When the fasting period is over, it is critical to break your fast properly with gentle foods that won’t disturb your digestive system.

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Pre-workout supplements can be a supportive tool while following an intermittent fasting plan, supplying much-needed energy for your workouts. But doing your research is critical as many pre-workout ingredients can trigger an insulin response that will break your fast.

With calorie-free pre-workouts containing caffeine, creatine, beta-alanine, and citrulline malate, you can reap the health perks they bring without impacting your insulin levels and breaking your fast.


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Laurence Pelo November 12, 2022

Very nice write-up. I certainly love this website. Continue the good work!

DoFasting November 14, 2022

Yay, we are happy you had a good read! Thank you.

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This is an evidence-based article that includes scientific citations. DoFasting’s professional writers and editors prepared the content, which a team of medical experts verified to be accurate.

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