Running on an Empty Stomach: The Lowdown

What happens to your body when running on an empty stomach and should you try it? In this week's blog we explore those questions.

Dennis Parkes

If you’re someone who likes to get up early and run before the day begins, then you may have considered running on an empty stomach, or even given it a try. It’s not always easy to eat properly in the morning, and you may not enjoy waiting for your food to digest fully. 

While it’s usually nice to enjoy a light snack or meal before running, and give yourself 2-4 hours, the appeal of jumping out of bed, having a drink and getting ahead of the day has its perks. Let’s take a look at how it may benefit you in your training. 

What happens to your body?

When you run on an empty stomach, your body is running in a glycogen depleted state, and there isn’t much energy instantly available for it to burn. Your body then turns to an alternative source, calling on its fat stores. Your body will do this naturally during the latter stages of a long run, when there is no food left to turn into energy.

So by cutting out the initial stage, you are training your body to access the alternative source of energy much faster, and improving your ability to make the transition when you run out of glycogen. Your body is therefore training to make the switch and becomes more efficient and familiar with this process.

Should you try it?

Basically, it depends on what you’re trying to achieve. Empty stomach running is not for everyone, but it can be more convenient and help you train for longer distance running. It’s recommended that you don’t do this too frequently, especially not for high intensity running and interval training. 

Also, your performance for these runs is highly likely to be worse than when you fuel your body properly, and it’s important to understand that running without food will be fine for short to medium distance runs but is not always the best way to train at high intensity and for longer distances.

Remember to stay hydrated, as running on an empty stomach doesn’t mean you shouldn’t still drink something in the morning!