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Runner’s Gut: 6 Causes + 9 Easy Ways to Prevent It

Runner’s gut can be frustrating, surprising, and downright nerve-wracking. It shows up unexpectedly and stops any run right in its tracks. And while it can occasionally become a chronic problem, it usually occurs so sporadically that runners struggle to predict when it will occur.

What is runner’s gut?

Otherwise known as runner’s stomach, runner’s trots, runner’s diarrhea and multiple other names, runner’s gut describes the urgency to use the bathroom while running. It often comes on unexpectedly, and creates a necessity to find the bathroom immediately before an accident occurs.

Usually beginning as slight cramps, bloating or a grumbling sensation in the abdomen, runner’s gut issues progress quickly and can rapidly escalate to create a sense of urgency.

Although runner’s gut feels slightly different for each runner, it is never pleasant and hardly welcomed in any run or workout.

Why does runner’s gut occur?

Runner’s gut can occur for a variety of reasons, but luckily – most of which can be changed or altered to avoid issues in the future.

The underlying reason that runner’s gut occurs is because while running, blood is pulled from the abdomen and redirected to the muscles to facilitate the activity. If the body is in the middle of digestion, the reduction in blood supply can lead to a variety of disruptions.

All runners are susceptible to runner’s gut, but those who already have digestive or intestinal issues, such as IBS, are often at an increased risk when running.

6 Causes of Runner’s Gut

The specific cause of runner’s gut will vary from runner to runner, depending on their body, health, training, fueling and environment. However, most cases of runner’s stomach can be traced back to one of the following.

Meal Prior to Running

Even when consumed hours before a run, the meal we last ate can play a huge role in whether or not we suffer stomach issues while running. The timing and type of meal that was last eaten before a run might actually be causing runner’s gut to occur.

Meals that are high in fiber, whole grains, fat or protein all require more effort to digest, and have the potential to lead to a disturbance on the run. In addition, the timing of your last meal can have as much of an effect as what was eaten.

Finishing a meal within two hours of starting a run will likely mean that your body hasn’t fully completed digestion, and runner’s gut issues are more likely to occur.

Type of Fuel Before & During Running

The type of pre-workout fuel, as well as fuel consumed mid-run, could all have an impact on whether or not runner’s gut occurs. Fuel sources that are high in fiber, fat, artificial sweeteners, or just very calorie-dense might be difficult to digest when running.

Digestion is often slowed while running, which means that foods that are particularly taxing on the system might not be able to be properly digested. These digestion troubles can cause a variety of runner’s gut issues.

Timing of Pre-Workout Fuel

In addition to the type of fuel affecting digestion, the timing of fuel intake does as well. Fuel that is difficult to digest, consumed immediately or very soon before beginning a run, are more likely to cause runner’s gut.

Running Intensity

In addition to fueling, the type of run or workout often plays a role in the likelihood of developing runner’s gut. In general, the higher the exercise intensity, the more likely that stomach issues will occur.

Longer runs, or runs that are very intense – such as interval workouts or sprints – are most likely to result in runner’s gut problems.


An often overlooked cause of runner’s gut is dehydration. Without adequate fluid intake, the digestive system is unable to function properly. Dehydration, in addition to the movement and blood reduction caused by running, can really create a wicked case of runner’s gut.


Sometimes runner’s gut is caused by outside factors, unrelated to the state of the body. Consuming NSAIDs has been linked to stomach or digestive issues on the run. These anti-inflammatory medications can make digestion more difficult, throwing off the state of equilibrium in the gut even more so than running already has.

Does runner’s gut have long term consequences?

Luckily, in the majority of cases, runner’s gut rarely results in any lasting negative consequences. Most runners are able to recover quickly once they have the opportunity to use the bathroom.

However, in some cases, the gut remains disturbed for hours after the fact, resulting in multiple trips to the bathroom before things are finally resolved.

Chronic, extreme cases of runner’s gut might eventually fall into the category of colitis, which is inflammation of the gut lining. Colitis can lead to perforation of the gut lining, when not treated over time. In most cases, though, runner’s gut never develops into anything more serious.

Runner's gut is inconvenient and uncomfortable. Here are the causes, plus 9 easy steps to prevent it for good.

9 Ways to Fix Runner’s Gut Problems

While resolving runner’s stomach issues might require a bit of observation and experimentation, in most cases, it can be fixed relatively easily.

Runner’s gut – or runner’s trots, runner’s cramps and runner’s stomach – doesn’t have to be a common theme on your runs. Here are 9 ways to resolve it once and for all.

Space out your mid-run fueling

It is recommended that you begin fueling after about 60 minutes of running, and continue to consume small bits of fuel at regular intervals for the remainder of a long run.

Taking in small portions of fuel spaced evenly apart is much easier to digest than one or two large fueling breaks.

Avoid foods high in fiber, protein or fat before running

Foods that contain high quantities of fiber, protein and fat can all be difficult to digest. To set yourself up for success when avoiding runner’s gut, you’ll want to avoid foods that are high in these nutrients. Aim for light snacks, with simple carbs that are easy to digest.

Stay hydrated

Drink plenty of water before and during a run. Be sure to stay hydrated in the 24 hours leading up to your run, and bring water along with you to sip regularly during runs – even in cooler weather.

Use a food journal to monitor what works

Sometimes it can be difficult to determine exactly what is causing your stomach issues on the run. In order to more quickly and easily identify the culprit, try keeping a food journal for a few weeks.

Record everything you eat throughout the day, as well as during a run. Keep a record of how your body responded and what you felt during the run. When problems occur, see if you can identify any foods that were new or out of the ordinary and may have caused the issues.

Practice fueling during long runs

Trying something new for the first time is bound to create unexpected results – especially when it comes to digestion. To minimize runner’s gut issues, practice your fueling during long runs in training.

Stick to the same fuel sources, schedule and activity as you plan to do during a race. Stay consistent during your long runs and allow your body at least a few, if not all, long runs to practice this type of fueling.

Stay consistent with your schedule

Speaking of consistency, it’s important to stick to some semblance of a routine when it comes to fueling and eating before (and during) runs. If you regularly eat breakfast two hours before a run, keep it that way.

Running at a similar time each day will also help the body know what to expect and provide adequate time to digest before beginning.

Avoid medications

Since NSAIDs and other medications are known to cause digestive disturbances, the best bet is to avoid them altogether during training. If they are still needed, try to time their consumption with off days or times when your body has a while to process before running.

Train your gut to prevent issues

Training your gut is a great way to prevent runner’s trots or cramps in the future. Making a point to practice fueling from the very beginning of training will give your gut time to adjust and overcome any potential issues.

Aim for foods high in simple carbs

The best way to support your body in its digestion on the run is to consume simple carbs before and during a run. Foods such as white breads, pastas or cereals are quick and easy to digest – making them great options for pre-run fuel to give you energy.

7 Food Types that Cause Running Gut Issues

  • Sugary drinks or energy gels
  • Nut butters, oils, or fatty meats
  • Processed foods
  • Whole grain breads or pastas
  • Excess fruits or vegetables
  • Low calorie drinks or snacks with artificial sweeteners
  • Caffeine

The Best Foods to Help Avoid Runner’s Gut

  • White breads or pastas
  • Low sugar cereals
  • Oatmeal
  • White bagels or English muffins
  • Bananas or other small serving of fruit
  • Graham crackers or saltine crackers

Paying attention to the types of fuel you are consuming, as well as your timing, hydration, and anything else you are putting in your body will set you up for long-term stomach success. Runner’s gut is uncomfortable and downright embarrassing – but luckily, it is relatively easy to fix.

Taking the time to observe your body’s reactions and adjust the input might be all you need to eradicate stomach issues once and for all.

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