How To Avoid Stomach Issues While Running

Greenletes / Sports Nutrition / How To Avoid Stomach Issues While Running

These 7 nutritionist approved tips will stop that nasty pain in your stomach while running. Never have stomach issues again when running!

Running is one of the most amazing sports, but it can also be one of the toughest on your body. The creaky knees sore muscles and stomach issues are enough to scare some people away.

And while I can’t help you with the first two, I can tell you that stomach issues are not something you just need to suffer through while running. As a matter of fact, gastrointestinal (GI) discomfort is completely avoidable with the right nutrition.

What is runner’s stomach? 

We’ve all been there – mid-race and suddenly we have the urge to use the bathroom. This is not as uncommon as you may think. In fact, many athletes are all too familiar with the struggle of nausea, vomiting and diarrhea during a race. This is what is referred to as “runner’s stomach”. Runner’s stomach is as a result of not only the up and down jolting movement that comes with running, but also hormones and dietary factors. When we run, we produce the stress hormone, cortisol, which can cause the undesirable feeling of needing to use the bathroom. All these factors together can make your stomach churn!

What happens in the GI tract?

Blood is an amazing thing because it recognizes where your body has work to do, and it immediately travels to that region. During a run, your blood goes to the part of the body that is doing the most work–the muscles.

Because of this, the blood is diverted away from the stomach, and any food that is in the stomach just sits there. During the constant up and down running motion, any food left in the stomach will be jostled around and cause distress.

Even without food, the physical shaking of the stomach during running is enough to cause distress. Think about if I took your stomach out of your body and shook it up and down constantly for an hour. That’s pretty much what running does to your digestive system. A seasoned runner will eventually adjust to this feeling, but it will definitely cause problems for a new runner.

runners in a race

Lastly, even if you haven’t eaten in a while, your intestines is likely digesting some food. Running causes that food to move quickly through your intestines, which can make you feel like you need to use the bathroom. Unfortunately, this is just a natural occurrence that is less than ideal for runners. That being said, there are things you can do to help combat these issues, such as:

1. Avoid high fiber foods

A friend of mine recently told me she was so confused because she was eating cereal (necessary carbs) before running, but she was still experiencing constant stomach problems. It turned out that she was eating high fiber cereal.

The combination of high fiber foods plus running equals a guaranteed upset stomach. It’s best to avoid foods like cruciferous veggies, beans, bran, and high fiber fruit before a run. And if you’re race, lay off the high fiber foods the day before as well.

2. Stay properly hydrated

Dehydration can make it difficult for your intestines to absorb food. As a result, any food in your intestines will quickly travel to your bowels and create a sense of urgency for the bathroom. This is just another reason why staying properly hydrated is so incredibly important during running. [Find out how to tell if you’re properly hydrated here].

3. Give your body time to acclimate

Just like your legs and lungs have to build endurance, your stomach and intestines have to acclimate to running. Going from couch to 5K will definitely lead to an upset stomach. Train your stomach to handle the up and down motion of running by gradually increasing intensity, distance and speed.

And if you’re new to running, don’t try to drink a sports drink right away. The sugar in a sports drink helps with fluid uptake and to replace lost carbohydrates, but it can cause some GI issues. If you’re increasing your mileage and want to try a sports drink, dilute it with water at first and gradually move to more concentrated versions.

4. Don’t try anything new on race day

Many times, runners only use gus and gels on race day. That’s a surefire way to upset your stomach. If you run for more than an hour, you should supplement your run with a sports drink, gel or gu. Try these supplements during your training runs to give your body time to adjust. These products are meant to provide fuel quickly, so they quickly digested and may cause severe indigestion.

5. Don’t eat a large meal before

Remember how I said that the blood goes to your muscles and away from your stomach during a run? Well, a large meal can take 2-3 hours to digest. If it’s sitting in your stomach, it’s bound to cause some discomfort. If you feel like you need some pre-run fuel, opt for simple carbohydrates, like a piece of fruit, a swig of homemade sports drink, or a slice of toast.

6. Steer clear of sugar alcohols and high fat foods

Sugar alcohols found in sugar-free items have been known to cause stomach issues, like loose stool or diarrhea. You may not realize you’re eating them, so make sure you read the ingredients and look for things that end in -ol. High fat foods also take a long time to digest and can cause indigestion. Avoid fatty meals containing fried foods and fatty meats before a run.

7. Be mindful of coffee and tea intake

I’m a big supporter of caffeine at least 2 hours before a race, but caffeine affects everyone differently. If coffee or tea make you feel like you need to use the bathroom, don’t have it right before a run. And you may want to think of avoiding it on race day.

How to deal with “runner’s stomach” during a race? 

While prevention is always the best way to avoid GI issues, here are a few things that you can try if you find yourself with runner’s stomach during a race: 

  • Slow down: Slowing down your pace for 5-10 minutes can make a world of difference and may help to alleviate some of the symptoms you are experiencing.
  • Sip on water: Make sure you stay hydrated during a race to increase the absorption of any food in your intestines. Otherwise you may have the urge to use the bathroom if that food passes down into your bowels. 
  • Use the bathroom: Bathroom breaks aren’t ideal when you’re trying for a PR, but stopping to use the bathroom may actually help you to feel better and finish the race.
  • Fuel with bland food: If you need mid-run fuel, choose something bland like a banana, dried fruit or saltine crackers.

Why do I have stomach pain after running?

Some runners are able to get through a race without any GI distress, only to experience pain after crossing the finish line. There is a simple explanation as to why this happens, and luckily it can easily be avoided if you follow these tips and tricks. 

First, there is a chance you are dehydrated after a race and this can cause some stomach distress. Rectifying this is as simple as sipping slowly on fluid to not overload the system. 

When you run long distances, most of your blood gets diverted to your muscles and away from your stomach. Less blood flow to the GI tract also means that the food you’ve eaten during the race may not have been absorbed and is still sitting in your stomach. This can cause discomfort and symptoms such as bloating, cramping or abdominal pain. 

If you have an upset stomach after a run, you’ll want to stick to relatively bland foods, like crackers, bananas, rice, yogurt and toast. Avoid food like raw veggies, fatty foods, milk and coffee as these may agitate your symptoms further. 

If you want more insider tips about fueling for running, check out The No-Brainer Nutrition Guide For Every Runner! 


  1. akissofskinny

    Great post! Keep it up:)

  2. Lindsey

    As someone with IBS, I’ve absolutely had more than my share of stomach issues when running. Thanks for such a helpful article!

  3. Meme

    Love all of the helpful tips to think about before my next run!

  4. Liz Shaw

    It’s crazy how simple tricks can really boost our performance. Thanks for this!

  5. Lorie

    So so so good to know. Passing this one on to my friend who is just getting into running!

  6. Tawnie Kroll

    I wish I had these tips when I ran in high school and college! Thanks for sharing !! So true!

  7. Emily Kyle

    Admittedly I am not a runner but I am very excited to share this with clients!! Thanks Natalie!

  8. Cedar

    Just stumbled across this post and am so grateful! I have bad stomach issues while running, which has forced me to find other forms of exercise over the last few years. But now I’m trying to get back into it. I think the key for me will be going slow (I’m bad at slowing down) and definitely experimenting with having low fiber foods before a run. Thank you for the tips!

    • Natalie Rizzo, MS, RD

      It’s funny because slowing down is hard for most runners, but it definitely helps. So glad you found my site and got some useful info from the article!


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I’m Natalie Rizzo, an NYC-based Registered Dietitian.

My mission is to help everyday athletes fuel their fitness with plants.

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