If you eat energy-rich food and drink isotonic drinks before running, you will feel great and have more energy, but only if you consume it at the right time.

In this article, I have explained what happens when you run on a full stomach and what and when you should eat to feel great during a run.

can i run on a full stomach

Can I Run on a Full Stomach?

Running on a full stomach will negatively affect your running performance. As a general rule, it’s recommended to wait for 3 to 4 hours after a large meal before running. That way, there will be no negative effects such as nausea, cramps, bloating, and fatigue in the legs.

Below you will find out what happens to your body when you run on a full stomach, and when and what you should eat to run without any negative consequences and be full of energy.

What happens if you run on a full stomach?

If you run on a full stomach, you may experience nausea, cramps, bloating, and fatigue in the legs.

This happens because the blood, which is needed to supply your muscles with oxygen, is sent into your stomach in order to absorb nutrients from food. Right after a meal, blood flow to the stomach and intestines is significantly increased so that your body can absorb nutrients from the food.

Negative consequences occur because neither your muscles nor the stomach get the amount of blood they need to perform their tasks efficiently. Food in the stomach cannot be adequately digested, while the muscles used in running start to tire much faster, as they lack oxygen that allows them to function at full strength.

Due to that, it is advised that you avoid any form of exercising right after a large meal.

When should you eat before a run?

In several places, you will read that it would be good if you postponed running for at least two to four hours after a meal. In reality, there is no single magic number that says how long you should wait, since not all meals or runners are the same.

The basic idea is that you do not require your body to simultaneously send large amounts of blood into your stomach (to digest food) and into your muscles (to run longer and faster).

If you do this, your body will try to force you to stop running by making you feel nauseous. If you do not stop running while you feel nauseous, your body will simply discard the food that it cannot digest at that moment, that is, you will vomit the remainder of the food.

Depending on the size and contents of a meal, a different amount of time is needed for it to be successfully digested. Fats and fibers take the longest to be digested, proteins take a bit less, while carbohydrates take the least.

Therefore, if it is a large meal containing fats, fibers, proteins, and carbohydrates, wait for at least three hours so that your stomach can absorb nutrients from the food. On the other hand, if you ate a smaller meal that contains proteins and carbohydrates, wait for two hours. Meanwhile, drinks and energy gels that only contain carbohydrates can be digested within just one hour.

That way, you will allow your body to digest the food completely, and you won’t be running on a full stomach.

Tip

Keep in mind that there is no single definition of what a large and what a small meal is. What you consider a large meal, someone else might consider a small meal. It is up to you to listen to your body and, depending on the meal, wait so as not to run on a full stomach.

Beginners are advised to wait for at least an hour even after a small meal before they go running, as they are not familiar with their body.

None wants to feel nausea or stomach cramps while running and feel as if they are going to vomit, which is the worst-case scenario when you run on a full stomach.

More experienced runners know their body quite well as they’ve discovered through trial and error what and when they need to eat in order to feel great during running.

Tip

If you find it hard to eat on the day before a race due to excitement, make sure that you have a hearty dinner the day before that. On the day of the race, eat only the food that you are used to, and try the food that you are unfamiliar with before lighter workouts so that you don’t ruin the race with unnecessary stomach pains.

It is good to drink an isotonic drink, eat half a banana, or an energy bar around twenty minutes before a race or a tougher workout, as they are a good and fast source of energy.

when should you eat before a run

What should you eat before a run?

The meal you eat before running serves to keep you from feeling hungry before and during running, and to maintain optimal blood sugar levels. The meal should contain a lot of carbohydrates, a moderate amount of protein, and be low in slow-digesting nutrients, such as fats and fibers.

If you run in the morning, you can run on an empty stomach or have a small carbohydrate-rich meal around twenty minutes before running, since your reserves have been depleted during the night.

You can eat whatever you want before running in the afternoon, but keep in mind that your body needs to digest the food. Therefore, it is important to take a pause between the meal and running.

Tip

Keep in mind that fats take the longest to digest. Therefore, if you don’t have time to make the necessary pause, eat carbohydrates.

More complex foods, the ones that nutritionists usually recommend, do not make a good meal before running as they require a lot of time and energy to digest. They are ideal for recovery after training.

Tip

For an after-run meal, choose food that is high on proteins, carbohydrates, fibers, and fats. Such a meal will keep you full for a long time and will allow you to recover your muscles and replenish your glycogen stores.

Here are some ideas for pre-run meals and snacks:

  • Pasta with tomato sauce
  • Bread and honey
  • Oatmeal
  • Thin-crust pizza with cheese and vegetables
  • Cereals with milk and banana
  • Pancakes with syrup
  • Energy bars

Matea Matošević
Matea Matošević

Article by:

Matea Matošević

Hi, I’m Matea! I’m Olympic Marathon Runner, founder, and writer behind OLYRUN.com. On this site, I provide help in the form of my knowledge and experience to all who love running and active living. Read more…

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