Swimming on an Empty Stomach: Good Idea or Bad Idea?

There has been a long-held notion that people should wait at least thirty minutes after eating before swimming. If you’ve heard of this idea before, you’ve probably wondered as to whether there is any merit to the statement. When I began swimming regularly, I often wondered if it was a good idea to swim in a fasted state.

Swimming on an empty stomach is convenient for morning workouts and is supportive of maintaining a caloric deficit. However, fasted swimming has a lower potential for muscular growth. You should fast before your swim if you want to lose weight and eat before your swim if you want to build muscle.

Below, we’ll discuss the various pros and cons of swimming on an empty stomach. Following that, we’ll analyze what time is best to eat before a swim, along with different examples of healthy foods that can successfully fuel your swim workout.

Benefits of Swimming on an Empty Stomach

To start, we’ll delve into the positives of swimming in a fasted state. Afterward, we’ll conduct a similar analysis on the negatives of swimming on an empty stomach.

Convenient To Do in the Mornings

For one, those that want to start their day with a refreshing workout in the pool can do so without having to go through the hassle of preparing a meal and eating it beforehand.

Many people out there depend on an early morning swim to start their day off right. They view their swim workout as the spark of energy they need to give their day momentum and approach their daily tasks with renewed vigor.

However, it can be a bit troublesome to do this if a swimmer has to worry about eating something quick before the workout. Everyone has a busy schedule, and there’s only so much free time to work in the morning. Meal prep takes this precious time away when it could be devoted to the actual workout itself.

Plus, not everyone has an appetite in the morning, so eating a full morning meal may not even be an attractive prospect to these people. It would be much more beneficial for them to head to the pool as soon as they wake up and avoid wasting time unnecessarily.

Supportive of a Caloric Deficit

Aside from the convenience factor, swimming on an empty stomach is also favorable for establishing a caloric deficit.

As a quick reference, a caloric deficit describes a situation where an individual consumes fewer calories than what their body expends within a fixed time interval. Since the body does not have a sufficient amount of calories available from food and drink alone, it must resort to fat stores for energy. Under some circumstances, physical activity may force the body to break down muscle for energy if the caloric deficit is too severe.

A person can put themselves into a caloric deficit by two methods:

  • Taking In Less Calories: By cutting down on the calories consumed through food and drink, there are less calories made available for cellular function. Consequently, fat stores are burned to make up the energy needed for these metabolic functions.
  • Being More Physically Active: When the body is more physically active, it is forced to expend additional energy. Thus, the body burns through the calories provided by food and drink at a quicker rate, forcing the body to burn through fat reserves instead.

Swimming on an empty stomach accomplishes both of these things simultaneously. First, it reduces caloric intake by taking breakfast out of the equation and compressing the eating window. Second, it raises activity level by forcing you to get up and move rather than remaining in a stationary position.

Consequently, the body is more apt to burn through excess fat to fuel the body, leaving you with a lower body fat percentage than before. This aligns with the theory of intermittent fasting. For those who don’t know, intermittent fasting is a trending weight loss diet where an individual voluntarily refrains from eating for an extended period of time to limit daily caloric consumption (source).

Most people choose to intermittently fast from the time they wake up to the afternoon, which would fit perfectly with a fasted morning swim. If the convenience and appeal of intermittent fasting interest you, swimming on an empty stomach may be something that you want to consider incorporating into your regular morning routine.

Drawbacks of Swimming on an Empty Stomach

Unfortunately, not everything about swimming on an empty stomach is all that beneficial. Below, we’ll discuss the most glaring flaws of swimming in a fasted state.

Less Energy Heading into the Workout

One of the foremost drawbacks of fasted swimming is a lack of pre-workout energy. The body heavily depends on the calories from the food and drink you consume to endure the rigors of swimming. In the absence of these calories, there’s a much greater likelihood that you’ll see a dip in your swimming performance.

There have been multiple research studies conducted around this topic that has application to both swimming and exercise in general.

For example, researchers did a recent study to analyze the effects of pre-exercise carbohydrate feeding on athletic performance. This study was meant to address the negative stigma surrounding eating shortly before working out.

After gathering and scrutinizing the data in full detail, the research revealed that any dip in performance associated with pre-exercise carbohydrate feeding was minimal at best. In fact, carbohydrate consumption in the hour before the physical activity even improved performance in some cases. Jeukendrup and Killer made the following statement about their findings:

“It can be concluded that advice to avoid carbohydrate feeding in the hour before exercise is unfounded.”


In another study, the results showed a positive relationship between meal consumption three to fours hours before exercise and athletic performance, particularly for endurance activities (source).

Although further scientific studies must be conducted to prove the benefits of meal consumption before exercise definitively, the current evidence suggests that eating before swimming will result in a slight increase in energy levels.

Decreased Potential for Muscular Growth

An indirect effect of the decreased energy levels linked with fasted swimming is a decrease in muscle building.

Muscle building is heavily contingent on an individual’s work capacity. The greater the training stimulus that’s presented to the muscles, the greater the opportunity for growth. This way, once the muscle fibers tear, they can fuse and come back larger than before. This is the underlying premise behind how muscle hypertrophy works (source).

If the muscles fail to undergo sufficient mechanical and metabolic fatigue, then the muscles will not have any reason to grow. For this reason, it’s critical for swimmers to continually push the envelope and progressively challenge themselves with a greater physical workload with each swimming session. Otherwise, muscle mass will remain stagnant.

Since caloric intake is a vital component of providing the energy for a swimming workout, it may be considerably more difficult for a person to up their work capacity in a fasted state. They may require an extra energy boost from a pre-workout meal to help them push past their plateau and tear more muscle fibers.

Misconceptions Surrounding Swimming on an Empty Stomach

Now that we’ve discussed the pros and cons of fasted swimming, it’s time to address some common misconceptions about eating on an empty stomach. Understanding these misconceptions may help you see this topic in a new light to make informed decisions about what’s most beneficial to you and your personal fitness goals.

Myth: Eating Before You Swim is Dangerous

It had been believed for some time that eating before swimming was a hazardous practice. The theory was that the blood needed to drive basic swimming movements would be rerouted to the digestive organs, leading to severe cramps that increase drowning risk.

Fortunately, this theory has been proven false. The diversion of blood towards digestion is not nearly enough to result in any serious complications that would prevent an individual from swimming.

American Red Cross dispelled the myth that eating before swimming is dangerous with an advisory scientific review concerning this very controversy. In the review, American Red Cross even went as far as to say that:

“Currently available information suggests that eating before swimming is not a contributing risk for drowning and can be dismissed as a myth.”


To date, there have been no known drowning deaths attributed to eating before swimming. This myth arose because a Boy Scout Handbook from 1908 warned against eating before swimming. The handbook claimed that eating 90 minutes before a swim would cause a person to drown, even declaring that such a fatal mistake would be their “own fault” (source).

Luckily, since this myth has been debunked, more and more people are getting to the truth of the matter and dispelling their unfounded swimming paranoia.

Myth: Fasted Cardio Burns More Fat than Regular Cardio

Another popular myth related to this topic is the notion that fasted cardio burns a slightly higher amount of fat than regular cardio.

The theory was that the body would be much more likely to turn to stored fat for energy as opposed to carbohydrates when performing fasted cardio. Although this notion did prove to be true, it only monitored the fat-burning effects during the workout itself. Researchers failed to take into account the fat-burning effects pre-workout and post-workout.

Once studies were conducted analyzing the amount of fat burned over a prolonged time interval (pre-workout, during the workout, and post-workout), the results were somewhat surprising.

One convincing study showed that if you burn more fat during a cardio session, you’ll burn less fat in the 24 hours after that cardio session (source). Consequently, fasted cardio and normal cardio burned relatively equivalent levels of fat overall.

If you want the full breakdown of why fasted cardio and regular cardio are equally effective, the following video by Jeff Nippard provides an in-depth explanation of what you need to know.

In short, swimming in a fasted state will not burn any more fat than swimming in a satiated state. Either way, a swimmer will burn the same relative amount of fat if swimming intensity and duration are fixed.

What is the Best Time to Eat Before a Swim?

Since we’ve established that meal consumption before swimming is completely safe, you’re probably curious about whether there’s an ideal time to eat before swimming to maximize performance.

The general recommendation is to eat approximately two to three hours before any physical activity, particularly for larger meals. If you do choose to eat within an hour of your swimming workout, however, it would be smart to consume carb-based or protein-based foods that are readily digested. In addition, to optimize performance, stay away from high-fat foods within two hours of the time you plan on swimming (source).

Your individual needs may vary from these general guidelines. Ultimately, it would be best if you experimented with your nutrient timing to figure out what works best for you and your fitness aspirations, as there’s no definitive answer to this question as of yet.

Good Foods to Eat Before Swimming

If you do decide to forgo swimming on an empty stomach, here are some healthy options to try out before your next swim (source):

  • Banana with Almond Butter – This light, low-calorie meal is an appealing option for those looking to shed a few pounds. Not only does this meal taste good, it also supplies enough energy to get you through the entirety of your pool workout.
  • Egg Whites & Whole Grain Toast – This protein packed meal is ideal for swimmers that are primarily aiming to build muscle. Just be careful to carefully portion the meal. If your portion meal is too big, it will sit heavy in your stomach during your swimming session.
  • Fruit Smoothie – A blend of healthy fruits is perfect for increasing energy levels going into a rigorous swimming session. A meal like this can make a noticeable difference in how much distance you’re able to cover over the course of the workout.

As a side note, keep careful tabs on your hydration levels before swimming. Your water intake is equally, if not more important than what foods you eat pre-swim.

The Bottom Line

There are no serious safety implications tied to your decision to eat or fast before a swim. Swimming on an empty stomach is largely considered to be favorable toward weight loss goals, whereas swimming fully satiated is thought to be better for muscle-building purposes.

Whatever your goals are, be sure to monitor your diet and hydration levels, as these factors are often what make or breaks an individual’s fitness goals.

All content written by HydroPursuit is for informational purposes only. The material found on this site is not intended to replace professional medical advice, treatment, or diagnosis. Consult with an accredited health care provider prior to initiating a new health care regimen.

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Austin Carmody

I am the owner of HydroPursuit. I enjoy kicking back and getting out on the water as much as I can in my free time.

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