How Long After Eating To Run?

How Long After Eating To Run?

So you’re wondering how long you should wait after eating to run.

The answer is it depends.

Here’s the short of it: if you’ve had a big meal, you should wait about 3 to 4 hours before running (preferably 4). If you’ve had a light snack, waiting a minimum of 30 minutes should do the trick. Oh, and if you’ve had more than a light snack but less than a big meal, you can probably get away with only waiting 2 hours before you decide to hit the pavement.

But there’s more to it than that – how do you know what constitutes a large meal? Or a light snack? Or whatever’s in between?

Should the intensity of your run make a difference in your decision? What about the distance you’re planning on running?

Hell, does what you eat matter?

Let’s take a closer look.

Running after Eating

But first, let’s take a look at what happens when you eat and then run immediately afterward.

The obvious effects – the ones most felt – are cramping and problems with digestion. These two are essentially related. But it’s the body’s digestive process that’s really the key here.

Digestion demands a lot of energy from the body. This is the reason people tend to feel sleepy after a particularly large meal – to digest more food the body requires more energy. Makes sense, right?

This energy is used to direct more of your body’s blood flow to the stomach and other relevant internal organs. Now, because these are hogging a larger share of blood flow than usual, that means your large muscle groups are receiving less blood than they normally would. Large muscle groups include arms and legs, both of which are very vital to running.

But if you decide to run while your body’s trying to digest, your body will try to compensate. It’ll redirect some of the blood flow going to the stomach and pump it back through the large muscle groups. And that’s where the problem is: the body just isn’t designed to digest and exercise at the same time. Hence, you have the discomfort and the stomach cramps and the GI distress.

That’s why running directly after eating should be completely avoided. It’s not good for your health, nor for your running goals.

So How Long Should I Wait After Eating to Run?

Again, it depends. Let’s break down our short answer just a little bit.

After eating a large meal, wait for at least three to four hours before running. And what’s a large meal? It’s all subjective – different from person to person – but a good rule of thumb is anything over 400 calories should be counted as a large meal. If it hits the 600 calorie mark, then it’s definitely a large meal.

After eating a small meal, wait for at least two hours before running. A small meal is around 300 – 400 calories. Again, any more than that, and it’s large.

If you’ve only had a light snack, then 30 minutes to an hour should suffice. A light snack is 150 calories maximum.

Other Considerations

  • If you’re running a very long distance – like if you’re competing in an ultramarathon, for example – then you have to eat during your run. The rules are different then because your body is using up all its glycogen stores and losing electrolytes and fluids by the bucket-full. This, of course, requires its own article (coming soon!). For now, it’s sufficient to know that the same rules as above apply for how long you should wait before embarking on a long run.
  • What you eat matters. If your light snack is rich in fiber – wait a lot longer than 30 minutes. Anything that’s too hard to digest will cause you digestive distress and hamper your efforts on your run. Spicy foods too should be avoided even a day before a run.
  • For moderate runs of about 60 minutes, you can be a little looser with the rules. You don’t even have to eat before them.
  • If you suffer from what’s colloquially referred to as “runner’s diarrhea,” it’s best not to eat anything at least two hours before you run. But what’s better than that is to consult your doctor and figure out what foods or beverages exacerbate your issue (and then just cut those out completely).

Helpful Resources

For more information on what to eat before a run and when, click here.

Here are some of our articles on carbo-loading before a run, what to eat after running, what the best snacks are to eat after running, and why protein should be one of your major dietary focuses. And while food is important, don’t forget to make sure you’re consuming enough fluids too, before and after you run.

And that’s all there is to it: everything you need to know about how long to wait after eating to run.

Questions? Concerns? Be sure to let us know in the comments below.


  1. NIDDK