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No Guts. No Glory - the pathway to the endurance podium runs through the stomach

You’re 8 hours into an endurance race, you’re pushing on, pushing hard, you’re feeling strong, you’ve trained for this and you’re executing it perfectly.

You are an ultra-racer!

But then you feel it. You know what I’m talking about. That feeling of fullness in your upper abdomen, then there’s the first burp, you start to lose the taste for food, you sense a prickling of nausea, which becomes full blown pretty soon after.

Now you can’t get food in, in fact it insists on coming out! Energy stores are being depleted mile after mile and you’ve got a long way to go.

Panic mode sets in. DAMN!

Your stomach is now running the race and are a passenger on the gut-train.

I’m writing this blog for one reason only, to help you fall a little in love with your stomach or at least have a little more respect for it.

Maybe then you’ll treat it better.

‘Down the hatch’, ‘get it in you’; many athletes fire food in with little thought of chewing it first.

You simply expect the stomach to go along and do it’s thang, whatever that thang is.

Well, your stomach’s thang is really quite remarkable.

It’s got a pressure pump, a rhythmic mixing pump, a grinder and a filter. It exquisitely choreographs the receipt of food and fluid of varying physical and chemical compositions; it mechanically mixes and hormonally tenderises; it grinds through various mechanical operations until each particle is about 2mm.

Then it puts it through a final filter before sending a perfectly timed message, through the nervous system, to the pyloric sphincter or opening of the small intestine. Without you feeling a thing, small amounts of perfectly processed food, now known as ‘chyme’, are rhythmically released into the small intestine where they begin their magical journey to make you energy and sustain your life.

Thank you stomach!

It all works perfectly well, until…you get in the way! And before we get to the things you throw ‘down the hatch’ let’s remember that you have already folded yourself over the handlebars of a bike and diverted blood supply away from this vital organ to your muscles or if you are an ultra runner you’ve flying up mountain sides disrupting the rhythm of your stomach with countless foot strikes. Those add up you know!

But that’s ok, your stomach is made of tough stuff. It can expand 10-15 times it’s empty state volume without a significant increase in pressure. You’ve got room to play with.

But that flexible, tough little organ has rules.

Such as, water and low concentration fluids (we’ll talk about that later) are purposefully navigated through the stomach quickly, with 90% being through within the hour. Even quicker if they are cold.

Digestible solids, and by that I mean things you’ve chewed, will leave the stomach after they have been mechanically and chemically ground down to 2mm in size. So if you want them processed quickly and with ease then chew them, chew them well and within 2 hours roughly 50% will have moved into the small intestine.

Large solids are retained and then dumped into the small intestine during a rest or inter-digestive period (usually sleep), which is perhaps part of your race strategy but to be forced to take a sleep is not ideal. So if you insist on dumping large solids down that hatch, one of two things will inevitably happen.

Your vagus nerve will send a message to either contract - your food is coming up - or relax -your food is going down, all the way down - and you better find a hedge quickly!

Lovely stuff. Are you falling in love yet?

You see, I love an organ with clear rules, an organ who can stand up for itself, an organ who refuses to be nutritionally bullied.

One industry who doesn’t love the stomach is the sports marketing industry. What they do love are highly concentrated fluids, gels, and foods.

They’ve sold the need for energy. Lots of it and instantly.

They’ve sold the need for 90g of simple sugar per hour, no wait, 120g of simple sugar per hour!

And to be fair maybe that’s possible in a controlled laboratory setting but an endurance race ain’t no lab.

It’s also possible that the stomach can indeed handle high concentration foods and fluids for a short time, say 3-4 hours. After all you’ve got an expandable space. But it’s one thing to get it into the stomach and another thing entirely to get it out.

Plus, after 3-4 hours you’re just getting warmed up.

It’s as simple as this folks, a carbohydrate solution at 5% concentration, which is 5g per 100ml is navigated through the stomach just a little bit slower than water.

I use this as an example as it’s common to aim for 500ml per hour, which in this example would be 25g carbohydrate. Research tells us, that at this concentration roughly 70% moves through the stomach in an hour. But there’s a caveat, that research doesn’t account for heat, dehydration, rain, wind, sleep deprivation….or any of the usual suspects you meet in an endurance race.

You folks are kind of outside the research bell curve.

But seriously this steady stream of carbohydrate entering the small intestine is a great start for any ultra-cyclist or runner.

Research also tell us that when you start taking in fluids at around 10% concentration (10g per 100ml) the stomach’s emptying rate drops significantly to only 20% clearing the stomach within the hour.

Now, imagine what will happen in 8-12-24 hours if you keep that level of fuelling up.

Add highly processed and concentrated ‘energy bars’ and ultra-processed gels on top of that and the stomach simply becomes overfilled, over-concentrated and overwhelmed.

That exquisite dance of pressure and flow grinds to a halt, as does your performance.

So for the love of god and the newly found love of your stomach please follow the below rules because the adage of ‘no guts, no glory’ communicates a searing metaphorical truth for the endurance cyclist, runner and indeed adventure racer.

1. Deliver the most unprocessed, digestible solids you can find. Break them into small, bite sized pieces and chew them as well as you can. There are lots of options. Call me!

2. Drink your carbohydrate bottle mix at a concentration of between 5-8% and if you’ve got someone handing you a bottle, make sure it’s chilled.

3. Fluids are a great way of getting in carbohydrate without so much grinding needed so don’t discount the use of products like chocolate milk, sqeezables, blended soups or smoothies.

4. Instead of following a prescribed amount of carbohydrate per hour start figuring out what YOU can tolerate comfortably, while still maintaining performance. We all have to experiment with that, no exceptions. It’ll usually be between 0.5-1g carb per kilogram of lean body mass depending how metabolically flexible you are (another blog topic).

5. And remember that gels are the most concentrated of all at 25g of carbohydrate in just 2 tablespoons of fluid so please use them wisely. And here’s a bonus tip from a fellow Barr Ultra racer, an ice cold gel goes down a lot easier. That makes sense to me as it creatively stays close to the rules.

As endurance athletes you desperately need a steady supply of energy so we have to be creative. It’s one of the many challenges of endurance racing but it’s one where my expertise comes in handy.

There are many different fuelling strategies that balance the constant need for energy with the processing capability of your stomach. Carbohydrate cycling (no pun intended) is just one of them.

We can also nurture, cajole and even train your stomach to accept more if we alter conditions, and provide scheduled rests or modified inter-digestive periods.

So if you’re sick (literally) of your great performances being limited by stomach issues, please reach out.

I am here to help you reach for that podium.


Don't let gut issues limit your performance? Email me at and let's get work with your gut to create your best performance.

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