Pre-Workout On Empty Stomach: Good or Bad Idea?

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If you are considering a pre workout, then you might be wondering if it should be taken with food, or if it can be taken on an empty stomach.

Taking a pre-workout on an empty stomach might be suitable for you if you generally tolerate caffeine well and don’t have a sensitive stomach. However, if you are extremely sensitive to caffeine or have a history of gut issues, you are better off combining pre-workout with food prior to working out.

It is important to remember that if you are someone who is sensitive to caffeine, then consuming your pre workout in a fasted state could result in negative side effects such as increased anxiety and jitters, and even symptoms like nausea and diarrhea.

Key Takeaways

  • Taking pre-workout on an empty stomach will increase the rate at which caffeine is absorbed, resulting in a spike of energy more quickly compared with taking pre workout with a meal.
  • There are certain kinds of pre-workout that might be more beneficial if you are taking them on an empty stomach.
  • If you are going to take a pre-workout on an empty stomach, be sure to take it 10-15 minutes before you train, since it will not take long for its full effects to set in.

Is Pre-Workout More or Less Effective When Taken on an Empty Stomach?

While your pre-workout will still result in increased energy if taken with a meal, there is some evidence to support that taking this supplement on an empty stomach could increase the rate of absorption, which would ultimately have a positive effect on your workouts.

Study: Influence of carbohydrate on serum caffeine concentrations following caffeine ingestion.

In this particular study, the goal was to assess the effects of caffeine on the body is a fasted vs fed state.

The study took 14 healthy males and completed 4 different trials that were each 5 days apart. On 2 occasions, the participants were fasted, and on the other 2 occasions were fed a high carbohydrate meal before consuming either 6 or 9 mg/kg of caffeine.

It was found that peak caffeine concentration in the blood occurred after 60 minutes in the fasted trials, compared to the fed trials, which showed peak caffeine concentration in 120 minutes (for the 6 mg/kg group) and 180 minutes (for the 9mg/kg group).

Key Takeaway: Consuming a meal that is high in carbohydrates significantly reduced the rate of peak caffeine concentration in the blood, especially when compared to caffeine consumption in a fasted state. Given that caffeine is a main ingredient in pre-workout, this is an indicator that taking pre workout on an empty stomach could result in a faster surge in energy compared to taking it with a meal.

On the other hand, many people often do not recommend taking a pre-workout on an empty stomach, since it can increase the risk of experiencing digestive distress, or even increase feelings of anxiety, jitters, or crashes in energy levels.

For this reason, it is going to be largely up to the individual as to whether or not they feel as if they can tolerate taking a supplement that contains stimulants on an empty stomach.

Many people may be better off taking it with a bit of food in order to avoid potential negative side effects.

Benefits of Taking Pre-Workout on an Empty Stomach

Pros vs Cons of taking pre-workout on an empty stomach

It Will Have a Faster Absorption Rate

The obvious benefit to taking your pre-workout on an empty stomach is that it is going to absorb into your system faster than if you were to take it with food.

This will result in the stimulant working at a faster rate, meaning you can take it closer to the time of your workout.

It Will Not Break a Fast

The ingredients found in most pre-workouts have not been found to break a fast, since generally these supplements don’t contain calories

Therefore, if you are wanting to train in a fasted state, you could utilize your pre-workout on an empty stomach for energy, rather than relying on energy from a meal.

It is important to note that although a pre-workout supplement can benefit a fasted training session, eating enough calories throughout the day to support your body and your training is going to be important for your overall success, and you should not be relying solely on a stimulant for your daily energy source.

Could Help to Boost Fat Loss

While we know that in order to achieve fat loss, you must be in a consistent calorie deficit, studies have shown that performing training in a fasted state can potentially result in your body utilizing more fat for fuel. For this reason, some people favor working out in a fasted state, especially during a fat loss phase.

In addition to this, caffeine (which is a common ingredient in pre-workout supplements) has been shown to help reduce body fat and aid in weight loss on the body. For these reasons, taking your pre-workout on an empty stomach could have benefits during a fat loss phase.

Drawbacks of Taking Pre-Workout on an Empty Stomach

Could Result in Digestive Upset

If you are taking a supplement that contains stimulants on an empty stomach, you have a greater chance of experiencing digestive distress, especially if you are sensitive to ingredients like caffeine. Common complaints of taking pre-workout on an empty stomach include things like nausea and diarrhea.

For example, when I was reviewing Pre-Kaged Pre Workout, I noticed that I felt sick from taking it on an empty stomach.

If you have tried taking your pre-workout on an empty stomach and have experienced these symptoms, try taking your supplement with a small meal such as a protein shake and a banana, as this will help to slow the absorption rate of the pre-workout.

Could Cause Feelings of Increased Anxiety or Jitters

Taking your pre-workout in a fasted state could also increase feelings of anxiety or jitters, since caffeine has been shown to have these effects on certain individuals, and these symptoms are felt at a higher rate when caffeine is ingested in the absence of food.

This is also going to depend on each individual and how they tolerate and metabolize caffeine. Therefore, if you know you are someone who is highly sensitive to caffeine, you are likely better off sticking to a smaller dose of pre-workout and taking it with some food.

Could Result in a Large Crash in Energy

Although it might be tempting to take your pre-workout on an empty stomach for a faster rate of absorption, taking a supplement that contains stimulants on an empty stomach could result in a larger “crash” in energy only hours after taking it.

In order to combat this, I recommend taking your pre-workout supplement with a meal that contains both protein and carbs, since this will help to stabilize your blood sugar and give you long-lasting energy, reducing the risk of a caffeine crash hours later.

Tips for Taking Pre-Workout on an Empty Stomach

tips for taking pre-workout on an empty stomach

Choose a Pre Workout With Minimal Ingredients

Taking a pre-workout that contains a ton of different additives and fillers could increase the chances of you experiencing gastric distress when taking it on an empty stomach. 

In the next section, I outline specific brands of pre-workout that are best to take on an empty stomach.

Take Your Pre-workout 10-15 Minutes Before You Work Out

In order to optimize the energy that a pre-workout on an empty stomach will give you, be sure that you are taking it around 10-15 minutes before you train. 

This will help to reduce the risk of feeling any dips or crashes in energy levels mid-workout.

Try Taking Half the Dose

If a full dose of your pre-workout on an empty stomach feels like too much and is causing negative side effects, try cutting the amount you are taking in half, since this could help reduce any negative symptoms you are experiencing, while still providing you with the desired energy boost for your workout.

Drink Plenty of Water

Drinking your pre-workout with plenty of water (around 8-10 ounces) will help to ensure that you are diluting the ingredients enough to the point where you are less likely to have any digestive upset or feelings of sickness.

On the other hand, drinking too much water with your pre-workout prior to your training session might make you feel a bit full and sick as well, so make sure you find a happy medium with your water intake.

Which Pre-Workout Is Best To Take on an Empty Stomach?

If you are going to take your pre-workout on an empty stomach, I highly recommend going with a high-quality brand that contains minimal ingredients, since this will reduce the risk of you dealing with digestive issues that can be caused by harmful additives, fillers, and sweeteners found in certain supplements.

1. Naked Nutrition Naked Energy

The Naked Nutrition Naked Energy pre-workout is a great option since the unflavoured version does not contain any added sugar or artificial sweeteners, which can be abrasive on the gut for certain people.

2. Ora Organics Natural Pre-Workout Powder

If you are someone who is highly sensitive to caffeine, you could also try the Ora Organic Natural Pre-Workout Powder, since it contains much less caffeine than most pre-workouts on the market at only 90 mg per serving, and derives its caffeine from sources such as matcha tea, yerba mate, and organic green coffee.

Does Timing Matter When Taking Pre-Workout on an Empty Stomach?

If you decide to take your pre-workout in a fasted state, then you will want to consider when you are going to take your supplement prior to your workout.

Due to the fact that your pre-workout will enter your bloodstream much faster if you are taking it without food, taking your supplement around 10-15 minutes before you work out will help to ensure you have enough time for the stimulant to enter your system.

On the other hand, if you decide to take your pre-workout with food, it will take a bit longer for it to hit your system; roughly 30 minutes or so. Slowing down the absorption rate of your pre-workout can even be caused by eating a smaller pre-workout meal.

Note: Keep in mind that if you like to train in the evening, then taking a pre-workout before you train could affect your sleep. For this reason, I do not recommend taking a pre-workout in the hours before bed, since it can take up to 5 hours for the stimulant to leave your system.

Frequently Asked Questions

Do I Need To Eat Before Taking Pre-Workout?

You do not necessarily need to eat before taking your pre-workout supplement. However, if you notice side effects such as nausea, diarrhea, increased anxiety or jitters after consuming pre-workout or caffeine on an empty stomach, then eating a meal with your pre-workout could help to combat this.

What Happens If You Take Pre-Workout Without Eating?

If you take a pre-workout supplement in a fasted state, you will experience a faster rate of caffeine absorption and a quicker spike in energy. However, taking a pre-workout without food can also result in negative effects like digestive upset, increased jitters, and a sudden crash in energy shortly after consumption.

Does Pre-Workout Hit Harder on an Empty Stomach?

Taking pre-workout on an empty stomach has been shown to enter your bloodstream and take effect more quickly in comparison to when it is taken with food. If you are not sensitive to caffeine, then you could try taking your pre-workout on an empty stomach in order to feel its effects more significantly.


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About The Author

Colby Roy

Colby Roy is a holistic health and nutrition coach. She is certified through Precision Nutrition and has a passion for all things nutrition and healing the body. More specifically, Colby likes to work with clients who want to optimize their gut health and energy levels.

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