Run Before or After Breakfast? The Ups and Downs of Fasted State Training

Black woman, afro hairstyle, running outdoors in urban road. Young female exercising in sport clothes.

Running before or after breakfast?

If you’re looking for an answer, then you have come to the right place.

Training in a fasted state is a controversial topic.

For some runners (including me), it’s a part of our training, whereas for others, running on an empty stomach is out of the question.

In this article, I’ll look at some of the pros and cons of running on an empty stomach and explore whether you should run before or after breakfast.

Sounds great?

Let’s get started.

Fasted State Training Explained

Running on an empty stomach isn’t a complicated concept to understand. It simply means logging the miles after not eating for some amount of time.

More specifically, training in a fasted state refers to exercising when you haven’t digested any food for more than six to eight hours.

This often applies to runners who log their miles before breakfast in the early morning. You can also train in a fasted state when you exercise while in a period of fasting.

The Benefits & Downsides of Running On Empty

Training on empty may have some benefits. Some of these include the following:

Improved Mitochondria

Mitochondria is literally the powerhouse of the cell as it’s in charge of energy production in the body.

The more mitochondria you develop, the more energy you can produce. This means being able to run faster and further.

Mitochondria is improved by regular training—think long, slow runs—but research has also shown that fasting may increase mitochondria count even more.

Improved Fat Burn

Running in a fasted state may help if you’re trying to lose weight.

Don’t take my word for it. Research has reported that exercising in a fasted state may cause your body to intake less energy and consume more energy.

The principle is simple.

When your body runs low on glycogen stores, it’s forced to turn into fat storage to use energy.

This results in higher oxidation, the fancy for the fat burn process.

Don’t take my word for it.

Research published in Plos One examined ten subjects and reported that training in a fasted state improved fat oxidation over 24 hours when the session was completed before breakfast.

Improve Aerobic Endurance

Looking to improve your endurance?

Training in a fasted state may help.

A study found a link between fasted training and higher VO2 max.

Exercising in a fasted state has been correlated to higher VO2 max, which is the body’s maximum oxygen uptake during intense exercise.

Think of it as an objective measure of both aerobic endurance and overall fitness.

5K good time

Limit the Calories

Another way fasted exercise makes you lose weight is by helping you control your energy intake.

Research that assessed 12 subjects who exercised on an empty stomach consumed fewer calories over the next 24 hours.

The reason behind the reduced energy intake may boil down to the liver, which also stores glycogen.

Fewer Digesting Issues

Runners, especially long-distance runners, are no strangers to stomach issues.

In fact, run for an extended time, and you’ll be prone to digestive problems such as:

  • Nausea
  • Flatulence
  • burping
  • Diarrhea
  • Stomach cramps
  • Vomiting
  • Bloating
  • acid reflux
  • Intestinal cramps

These unwanted symptoms not only strike long-distance runners but anyone who exercises for long periods of time.

For some runners, avoiding fatty, spicy, greasy, or acidic foods does help, but some of us have a sensitive stomach.

Any food is bound to stir up trouble on those long runs.

When you run on an empty stomach, you won’t have that “full” feeling or the annoyance of food sloshing around in your stomach.

The Dark Side

Running on empty isn’t just sunshine and rainbows. The practice also has its downsides, depending on your fitness experience and training goals.

Let’s briefly check a few.

Limited Stamina

Your body needs fuel during training. When running in a fasted state, you might have less fuel in the tank, thus, less stamina.

For this reason

If you’re trying to take your endurance to the next level, training in a fasted state (way before your body is fat adapted) may limit your progress. In fact, you might get fatigued much earlier than normal during your workout.

You also run the risk of a low blood sugar level, which can leave you feeling shaky, nauseous, and lightheaded.

Muscle Loss

If losing fat is your main goal, running on empty—especially if your diet lacks protein—can put you at risk of losing muscle mass instead of fat.

Other Risks

As I stated in the intro, fasted training isn’t for everyone.

If you have any type of chronic condition, make sure to check with your doctor before you try any form of fasted training—or intermittent fasting, for that matter. It’s always better to err on the side of caution. It’s your health we are talking about here.

For example, fasted training may make you prone to exercise-induced hypoglycemia. This is especially the case if you already taking blood glucose medication.

So what should you do?

Whether you decide to run before or after breakfast, the key factors to pay attention to are your health and personal preferences.

So it’s really up to you.

If you feel like training in a fasted state, then do it. But if you experience any sort of distress, eat something before you head out the door.

How much to eat before a morning run depends on your personal preference. Your pre-run food is unique to you because everyone’s digestive system is distinct. No suit fits all.

But all in all, go for something light—something rich in complex carbs and some protein. This might be enough to provide your body with the fuel it needs.

Be Careful

If you decide to go the fasted running path, then, at the very least, start with light to moderate training. Then see where you can take it from there.

Slow down if you start to feel any unwanted symptoms.

Going for a long-distance run or doing a high-intensity session? These workouts require a lot of fuel, so it’s a good idea to have something in the tank.

What to Eat Before A Run

Choose wisely in case you choose to eat before heading out. Ideally, go for a light snack that has enough fuel to power your run without upsetting your stomach.

Awesome pre-run snacks include:

  • Whole-grain bagel
  • Banana with a tablespoon of nut butter
  • Low-fat granola bar
  • Fruit smoothie
  • Banana and an energy bar
  • Bowl of yogurt with berries
  • Cottage cheese with apple
  • Whole wheat toast
  • Cup of yogurt
  • Grapes with a few almonds

When To Have Breakfast After Running?

Ideally, have your breakfast within the first 20-30 minutes. Avoid going longer than two hours.

As a rule of thumb, shoot for a well-balanced meal of carbohydrates, protein, and fats. This should help speed up recovery, stimulate muscle protein synthesis and improve performance.

Ideal options of post-run breakfasts include:

  • Veggie omelet
  • Turkey sandwich with whole wheat bread
  • Salmon with quinoa and avocado
  • Yogurt and fruit

What’s more?

Drink plenty of water.