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.

Stomach & GI issues are some of the most common ailments among runners, but they can be solved with proper nutrition. A Registered Dietitian and marathon runner provides tips to do just that! #runner #run #sportsnutrition #runnernutrition

What happens to your stomach during a run?

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 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 sit 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.

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–#10].

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 something 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 a run

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.

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


  • Reply
    March 5, 2016 at 11:29 am

    Great post! Keep it up:)

  • Reply
    November 16, 2018 at 6:32 pm

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

  • Reply
    November 17, 2018 at 9:07 pm

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

  • Reply
    Liz Shaw
    November 18, 2018 at 12:58 am

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

  • Reply
    November 18, 2018 at 10:49 pm

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

  • Reply
    Tawnie Kroll
    November 19, 2018 at 11:19 am

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

  • Reply
    Emily Kyle
    November 26, 2018 at 10:22 am

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

  • Reply
    July 11, 2019 at 6:07 pm

    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!

    • Reply
      Natalie Rizzo, MS, RD
      August 6, 2019 at 10:25 am

      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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