An Athlete’s Guide: 4 Ways to Avoid GI Issues

An Athlete's Guide - 4 ways to avoid GI issues - Eat Spin Run

We’ve all been there. Whether you’re a runner, a gym-goer, or a group exercise enthusiast, I’m willing to bet you’ve had at least a couple of experiences with a less-than-happy tummy during a workout or race.

There are a lot of reasons why experts claim it happens, but a lot of the explanation centers around the fact that exercise puts the body under physical stress. All the lovely things we deal with as a result – cramps, stomach pains, bloating, and yes, runner’s trots – are all linked to the stress response.

ran marathon, didn't poop pants!

Nutrition plays a very obvious role, particularly what you eat before training and racing. Your muscles start working as your body gets moving, and all that blood flow that was once going to your stomach for digestion gets diverted  to those demanding muscles. As a result, whatever was in your stomach being broken down sits there like a rock, and that can be really uncomfortable!

So what’s a sweat-loving endorphin junkie with a season of races ahead to do? I’ve got 4 ways to avoid GI issues to offer you, all of which are tried and tested by yours truly.

1. Get your probiotics

Athletes and active individuals in general undergo more physical stress (including on the digestive system) than others, and probiotic supplementation is a great way to ensure that you’ve got the right balance of bacteria in the gut to keep things humming along as they should (If we want to be all science-y, we’d call it maintaining homeostasis.)

As you’ve probably heard before, we aren’t just what we eat, but we are what we absorb. You could be consuming a nutrient-dense diet (which is awesome – congrats!), but without a healthy gut microbiome, you might not truly be absorbing all those nutrients. Therefore, perhaps you’re not as well-nourished as you think. Probiotics can help keep the gut nice and healthy, repairing previous damage and improving your body’s ability to absorb those precious nutrients.

Ultimate Flora Critical Care Probiotic

One more thing: 70-80% of the cells that contribute to the body’s immune system are found in the gut. So, by supplementing with probiotics or eating lots of probiotic-rich foods, you’ll also be reducing your chances of getting sick. That means fewer missed training days, something that us athletic types with our eyes on the prize can’t stand!

As far as brands go, I’ve had the most success with Renew Life Ultimate Flora Extra Care Probiotic 50 Billion (formerly called Critical Care). This is a high-strain probiotic and really seemed to help when my naturopath decided that likely had leaky gut and an over-exposure sensitivity to spinach. (Yep, it’s actually a thing.)  If you’re not into supplements, you can also get probiotics through your diet by eating foods like…

  • Kefir, a fermented dairy product that tastes a bit like tangy yogurt with a thinner, almost milk-like consistency.
  • Sauerkraut and kimchi, or other fermented vegetables
  • Fermented soy products like miso (a salty soybean paste – this is the one I use), and tempeh.
  • Yogurt – but be careful. A lot of brands claim to contain probiotics but also give you a nice cocktail of sugar, artificial flavouring, dyes and other rubbish ingredients that aren’t real food. Read the ingredients list!
  • Kombucha (make your own and save lots of $$$ using my DIY kombucha tutorial!)

Homemade Ginger Orange Kombucha - Eat Spin Run Repeat

2. Record what you eat in your training log

Just like your workouts, be sure to also write down what you ate before. If you work out first thing in the morning, don’t discount the impact of the foods you ate the night before, and if you work out in the evening, your mid-afternoon nutrition should be accounted for.

When you start practicing your race nutrition (which you should definitely do at least a few times until you feel confident that it will work), write down what you eat before, during and after, and use all this information to inform your race-day nutrition strategy.

customized workout journal

In addition to the foods themselves, write down how you feel post-workout. It’ll be a result of a number of factors like your body’s recovery status, nutrition, workout intensity, weather conditions etc, but the more you record, the easier it’ll be to spot trends.

3. Be careful with key trigger foods

You probably know about any foods that don’t agree with you on a daily basis (outside of training and racing) and obviously you’ll want to keep avoiding those! However, there are a few known culprits when it comes to foods that trigger GI distress, and these include:

  • Cruciferous vegetables: This is a tough one for me, because I LOVE my vegetables! Broccoli, cauliflower, kale, Brussels sprouts, cabbage, turnips, collard greens, bok choy and radishes are all in the cruciferous veggie family, and they’re high in sulphur. What does sulphur smell like? Boil up a pot of any of these in your kitchen and that’s exactly what it smells like. While these foods are super nutritious, unfortunately they produce hydrogen sulfide gas when broken down in the large intestine. You may be ok with the smell of sulphur, but hydrogen sulfide smells like rotten eggs and I don’t know about you, but that’s not a smell I enjoy! Long story short: gas = discomfort, bloating, farts… you get it. Nothing you want to happen when you’re trying to run

Tangy Tempeh Stir Fry

  • Artificial sweeteners: Ever flipped over a packet of gum or ‘sugar-free’ sweets to find that it says “may cause a laxative effect if eaten in excess”? This is because artificial sweeteners like sorbitol can’t be digested, and when the digestive system comes across something useless to the body, it naturally tries to get it out! As far as gum goes, chewing it also means you’re swallowing extra air, which can also cause bloating. I kicked my gum habit about a year ago, and it’s one of the best things I’ve ever done!


  • Fructose: This isn’t a trigger food for everyone, but fructose can be a big culprit of gas and bloating for some people. It’s found naturally in dried fruits, grapes, apples, cherries, kiwi and blackberries. I’m not saying don’t ever eat them, but just be careful around training time. Similarly, if you’re struggling with finding something that agrees with your stomach during your races, checking your gels and sports drinks to ensure fructose isn’t one of the sugar sources may help.



  • Any high-fibre foods like beans and whole grains. Again, don’t get me wrong – fibre is a really important part of the diet and is key for healthy digestion – most of the time. But I don’t need to type out the bean song – the fact that it exists in the first place speaks volumes about why you want to stay far away from them pre-run! As for grains, they contain both soluble and insoluble fibre. The latter does not dissolve in water. It takes a lot of work for the body to digest, and this is normally good because high-fibre meals can help to keep us feeling satisfied throughout the day. Before workouts however, steer clear. You don’t want your body trying to break down fibre when your muscles could be using that energy to set a new PR!

black beans

4. Get your timing right

One of the reasons I prefer working out in the morning is because at that time, I don’t have a full day’s worth of food in me. My entire body has been resting for 7-8 hours and hasn’t been under much emotional stress during that time (unless I dream about something terrible happening, like Whole Foods running out of tahini).

While I’m a morning person, I appreciate that not everyone is. If you train after work, experiment with your meals and snacks until you find the timing that works best for you. Eating lunch at noon and nothing else all afternoon could leave you feeling tired and really hungry by 5, but if you’re running at 5:30, the last thing you want is to overdo it and have food jiggling around while you pound the pavement.

A better approach for a 5:30pm run might be to have a 200-300 calorie snack around 3pm, or if that can’t happen, a really simple carb-based snack such as a banana at 4:30. That gives you a full hour to digest.

pre-race breakfast of Mighty Flakes and banana

As for racing, again, this is unique to every individual but my very brief advice is this: Don’t eat anything that could cause problems the night before (Mexican or anything super spicy… probably not the best idea) and be prepared to get up early in order to allow at least 2 hours of digestion time. Waiting in line for the bathroom 3 minutes before the gun goes off is not fun, will stress you out, and will do nothing to make it easier to ‘go’! 😉

Seawheeze Half Marathon 2013 Gold Carrot finisher medal

[Tweet “An athlete’s guide: Don’t let GI problems get in the way of your next PR #runchat”]

I’ve got many more tips to offer, but this is getting to be a big post so perhaps I’ll do a 2-parter. In the meantime, I’d love to hear…

  • What are some of your go-to pre-race/pre-run foods? How far in advance do you eat them?
  • Any other tips to share?

6 thoughts on “An Athlete’s Guide: 4 Ways to Avoid GI Issues

  1. Such great advice- thank you! I’m going to save this for later. I want to get back into running again, but I remember how many GI issues that brings and am really hoping to avoid it this time around. It seems inevitable, but I’m going to take your tips and cross my fingers!

  2. What’s your take on coffee? Do you drink it? I drink a cup every day around noon…can’t seem to kick the habit. Not sure if I want to or if I feel like I should.

    1. Hi Jenni,
      I don’t personally drink it, but that’s not because I have anything against it from a nutrition perspective – I just don’t care for the taste! I love the smell and actually sort of made myself learn to like drinking coffee in university, but the only reason I did this at the time was to help me stay awake in my night classes (because I’m NOT a night owl!) However, now I just prefer tea. If it’s something you enjoy and really take pleasure in drinking at noon every day, I say there’s no reason to get rid of it. 🙂

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