What is “runner’s gut”?

Many athletes, both recreational and competitive are familiar with the term “runner’s gut”. This term describes debilitating symptoms that athletes commonly suffer during intense prolonged exercise such as stomach pain, cramping, urge to vomit or urge to defecate, among others. This may lead to the sufferer to being doubled over in pain with or without vomiting or with the need to urgently find a toilet. These symptoms can ruin key training sessions or even worse cause an athlete to pull out during an event.

What causes Runners Gut?

Diagnosing the cause of runner’s gut is a complex issue –something is causing stress on the gut which effects its absorption ability. The official scientific term “exercise induced gastro-intestinal syndrome” (1) sums it up nicely!
Dehydration is commonly mentioned as a cause, but so too is over hydration! Another explanation is that excessive carbohydrate loading (eg sports drinks and gels) can cause malabsorption during races. Every athlete metabolises carbohydrate and fat differently, and only by testing the gut extensively under duress can you get an accurate idea of what the cause may be.
World first testing!
Monash University’s Sports Dietetics research team (including our resident SSPC Dietitian Chris Rauch) lead the world in this testing.
In great news for athletes, research has shown that with as little as a 2 week gut training program, athletes that initially had great difficulty tolerating a high carbohydrate dose during endurance running had fewer symptoms, lower intestinal malabsorption and improved running performance. In simple terms, the gut is indeed ‘trainable’ within a relatively short period of time (2).

Who can be tested?

Basically anyone – runners, cyclists, any endurance athlete! SSPC Dietitian Chris Rauch is part of this Monash Research team conducting laboratory exercise tests for clients, with the testing regime available to the public through their specialised nutrition and exercise clinic at the University. It’s not easy – athletes are put under exercise stress for two hours (up to three hours for ultra-endurance athletes) whilst a raft of measures are taken, including testing of blood markers, gut absorption rates, fluid losses and the athlete’s metabolism of carbohydrate and fat.
With expert interpretation of the data collected, this Gut Assessment can help diagnose the cause of gastro-intestinal problems, providing the client with a detailed report including an action plan to address the issues. This action plan can include an accurate race nutrition strategy, explaining what quantities of fluid and carbohydrate should be ingested over specific time periods.

Who Could Benefit From A Gut Assessment?

• Anyone currently experiencing gastro-intestinal issues during sports activity.
• Any endurance athlete
• Anyone looking for a comprehensive analysis of their gut metabolism under duress, and developing a nutrition plan to use during training and competition.
• Those that just can’t “stomach” the goo and gels that your training mates rave about!
• Team/power sport athletes that have issues during or following competition.
• Athletes travelling to climates or environmental conditions they are unaccustomed to.

For those interested in a Gut Assessment, referral is not necessary, but an intial Sports Dietitian assessment is required.

Please contact Chris Rauch directly:`
Mob: 0488 999 917
Email: dietitiansspc@gmail.com


1) Costa RJS, Snipe RMJ, Kitic CM, Gibson PR. Systematic review: exercise-induced gastrointestinal syndrome—implications for health and intestinal disease. Aliment Pharmacol Ther. 2017;46:246–265. https://doi.org/10.1111/apt.14157

2) Costa RJS, Miall A, Khoo A, Rauch C, Snipe RMJ, Camões-Costa V, Gibson P. Gut-training: the impact of two weeks repetitive gut-challenge during exercise on gastrointestinal status, glucose availability, fuel kinetics, and running performance. Applied Physiology, Nutrition, and Metabolism, 2017, 42:547-557, https://doi.org/10.1139/apnm-2016-0453