David Roche urges that gut training is like any other part of our training: it takes time and intention. Here are his three rules for training your gut to improve fueling and performance.
So many athletes message me with the same lament: "I just can't do high-carb fueling without gut issues." I empathize with that feeling.
In 2023, I raced the Canyons 100k, my first race over 50k (and my first race fully committing to high-carb fueling). At mile 42, a gel came back up as soon as it went in, and my body proceeded to release the WRATH OF THE DEMONS BELOW on an innocent tree. The tree is still in therapy, and I uplift its mental health journey. Get the help you deserve, king!
Coming out of that race, I realized that the high-carb revolution needed to be paired with a revolution in how we think about gut training. For most people, it probably doesn't feel natural to consume 75-120+ grams of carbs per hour, along with all of the hydration and electrolytes needed to ride the modern performance wave. But what high-performance activity feels natural at first? Running definitely doesn't! If I took my first 10 or 100 runs as an indication of how the next 5,000 would go, I would have written myself off before I even got started.
The limited research provided a couple of clues. Gut transporters could get more efficient with specific carb ratios over short-term interventions, indicating that it was important to practice with what you'd use on race day. I think the biggest advantage for modern athletes is that our fueling tech is leaps and bounds better than what existed even 5 years ago. In addition, the feeling of "bloat" from consuming a lot of gels and liquids could go down substantially in just a week or two, leading to better performance too. The researchers called the phenomenon "more cushion for the pushin."
Those were the hints for an experiment that I conducted over the next year, culminating in being able to consume 150 grams of carbs and 1 liter of fluid per hour for the first 10 hours of a 100 miler at high altitude. Thank you, thank you, I'll hold for applause while we remove the gender-neutral panties from the stage.
(For me, the best combination is Science in Sport Beta Fuel gels, Precision 100 mg caffeine gels, and Skratch hydration.)
Simply put: everyone needs to do gut training. The big realization I had personally, then later in coaching, is that the gut needs to be pushed in the same way we push our legs and lungs. It's not as simple as just practicing a few times like you will on race day. No one would think they can run a fast marathon on a few marathon-paced runs and nothing else. But that's how most athletes approach gut training! Instead, we need to go beyond the demands of race day. That leads to the three rules for gut training.
Rule One: Do your race day fueling on every long run.
Practice it, make it second nature. I personally like athletes to have a gel on a set time structure (i.e. every 20 minutes, every 30 minutes). That will optimize gut transporters and get you 50% of the way there. That's where lots of athletes stop, and it introduces a problem. Training is almost never as stressful as racing, so what seems like it works on a long run might result in traumatizing trees when the effort is longer or harder.
Note: If taking in any gels is challenging for you, practice by taking one at 20-30 minutes after the start of every run you can (that's also a good rule for athletes with eating disorder history or REDs).
Rule Two: On at least 2-3 runs, go beyond race day fueling with hourly carb rate.
Here's where I see the biggest leap forward. Whatever your race day intake, go beyond that by 25% at least a few times in training. For example, if you want to consume 80 grams of carbs per hour in a marathon or ultra, go closer to 100 grams for some quality long runs. The treadmill is a great place to practice this sort of intervention. If you want your legs to perform, you do speed intervals. A similar overload approach seems to work wonders for gut transporters. This is especially important to do within the 2 weeks before race day, due to the rapid turnover of cells in the gut.
Rule Three: Every week or two, consume a significant portion of your hourly fluid needs all at once.
When I was trying to solve the gut training equation, I looked to competitive eating for some ideas. Those athletes often use fluid to train their guts, which makes a lot of sense based on the bloating research. For training, try drinking more fluid at once (not going beyond your needs, but concentrating the consumption into a smaller window). Anyone who gets their mid-run hydration from a water fountain is probably already doing this! If you can take 20-30 gulps from a fountain and then run away unscathed, you'll know you're ready to rock.
Honestly, I'm flabbergasted about what the gut can do. But just like your legs, you need to train it. Time to slurp.
