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How to Train a Runner's Gut

So you're one of the 30-50% of athletes (some studies suggest up to 90%) who suffer from GI distress during endurance exercise. Nausea, diarrhea, cramping - even if your symptoms are relatively mild, they can be uncomfortable - not to mention get in the way of your enjoyment of the run or your PR attempt. Why do they happen - and what can we do about it?

Why Runners Get the Trots

Exercise is a perfect storm for GI distress. The bouncing motion of running and the pressure on the stomach from sitting on a bike can cause issues. On top of that, high-intensity exercise directs blood away from the gut to the areas that need it more (like your heart and skeletal muscles), while gastric emptying slows. This makes it more difficult to digest what's in your gut. On race day, nerves can get in the way too - I know I've made more than one trip to the port-a-potty line when I was keyed up for a big event!

Nutritionally, poor hydration can make GI distress worse. So can eating foods that are slow to digest, like fiber, fat, and protein. In addition, taking in too much sugar (like eating a gel with no water, or drinking a concentrated sports drink) can pull water into the gut and cause symptoms.

Training the Gut

Some of these problems have relatively easy fixes - for example, if you're taking a gel, you should consume that gel with enough water to prevent an upset stomach. If race day nerves are your issue, you work on mental training and reframing high anxiety situations. But if you have a sensitive stomach, you might have just decided it's easier to train on empty and forgo the benefits of fueling.

Don't do this! You can't run on empty, and if you try to wing it with fuel for an event after not fueling during training, you have a higher risk of developing GI symptoms. But you can train your gut, just like you train your muscles and your cardiovascular system! Training the gut can improve your stomach comfort and ability to tolerate nutrition, which means YOU can fuel more effectively and perform better.

Here's how I suggest approaching training your gut.

1) Start small and simple.

Start with the amount you can tolerate. For example, if a banana and peanut butter toast upsets your stomach before a run, start with just the banana. If that's still too much - start with some Gatorade, a few sips of lemonade or another carb-containing sports drink of your choice. If fueling during the run is your issue, consider trying a product made from whole-food ingredients (Muir Gels, Huma Gels, and Spring Energy Gels are a few) that can be easier on the GI system, or try using whole foods like dates, crackers, or applesauce to start. Stop to eat them and make sure you're staying hydrated. Find what works for you - and start there.

2) Stay consistent and patient.

Training the gut doesn't work without practice. It's fine to adjust things based on what you're doing well with, but if you try twice and are still having trouble, don't give up. Maybe you need to slow down your pace for a little bit to make the nutrition work for your stomach. Maybe you need to eat a little earlier and give yourself 30-45 minutes to digest before you leave if it makes you feel sick to eat right before you head out the door. Make the adjustments you need, but don't bail too early. Training the gut takes time and patience.

3) Slowly increase what you're consuming.

When you've been tolerating a smaller amount of fuel for a few weeks, you can advance to include a little more. Maybe you can try the sports drink with half a banana, or a banana with dry toast instead of toast with nut butter. Maybe you start out with a hydration option that's more easily tolerated and slowly work in the beverage that will be available on race day. As you tolerate more and more, you can graduate back up to your original fueling plan - or continue to adjust and tweak as you go!

4) Fuel your PR!

No explanation needed here - once you've nailed your fueling strategy, you're ready to test it out in a race setting! Consider trying out your plan in a race before your goal race or with a key workout, so you know how your stomach will respond when nerves and pressure are turned up.

Having your stomach ready to go on race day is just as important as having your legs rested and your mental game on point. GI issues can make or break a performance, so take the time to train your gut and avoid any issues that might derail your breakthrough race!

What's your go-to race day fuel?

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