Fuelling Guide to Prevent Gut Issues During Endurance Races
If you're struggling with GI distress during marathons, ultra marathons, long mountain races, randonneuring on the bike, bikepacking, fastpacking, iron man triathlons or any other endurance based activity, we've created a one of a kind endurance fuel database that we use below to filter, sort and show you fuel choices that answer your specific gut issue queries.
We've tried to make this as simple as possible, we share what we have researched and learned ourselves about fixing gut issues and then we direct you to our database which gives you fuel options to try based on what we filter, sort and refine.
Before we dive in to the suggestions, we need to know what areas are potentially causing you issues, and there is more to this than just the stomach.
The gut is made up of multiple organs, not just the stomach and If you're struggling with GI distress during endurance activities, you'll be having an issue with one of or more of the following organs.
- Stomach
- Small intestine
- Large intestine (colon)
- Liver
- Pancreas
Most GI issues stem from how the stomach and intestines process fuel under exertion and the suggestions we go through below cover these organs and the issues they may have in different ways.
My name is Martin, and I'm a lifelong endurance athlete. I race myself and work with trail and ultra-runners as a documentary filmmaker, so I've seen firsthand how debilitating stomach issues can be during a race. I vividly remember being on top of a mountain at 2am in the Alps during a 100km ultra-marathon, battling horrible stomach issues and thinking my race was over.
After spending an entire year building up to that race, along with years of training to even get to that point, it was frustrating to realise that something as simple as what I had eaten (or hadn't eaten) was dictating how my race would unfold. That experience led me to combine my background in data science with my passion for endurance sports, and to build the Find Trail endurance fuel discovery app.
It is the biggest and continually growing database of endurance fuel options on the internet, we are not limited by stock or products like most websites, when we find a new gel, energy chew or powder from a sports nutrition brand, we add it to the database so that you get the best fuelling answers on the internet, because we have all the fuel options added to our database.
Unlike online endurance fuel stores that only offer a couple of basic filtering options, there is no way to get real fuel answers and suggestions based on your specific fuelling queries. Our tool lets you truly break down and find endurance fuels, helping you find exactly what works for your body.
How we do this is with over 50+ individual data points per fuel, detailed categorisation, and advanced filtering and sorting options. The database helped me uncover the exact fuels that work for me based on the questions I asked it. It is virtually impossible to go to an endurance fuel marketplace or online store and ask it, which energy gels do not have fructose in them and have the most carbs per 100g, are the cheapest on the market, taste like orange and are a nice medium gel consistency and here is the result for that specific requirement.
And it is this tool that we will use and link to in the examples below to help you work out your stomach issues, step by step. After each link to the suggested fuel choices which can help with a specific query, we show you how we filtered, sorted and added data on the fuel database underneath each section.
If you find that you may have a few different fuelling options that might work for you, don't forget to head on over to our direct side by side endurance fuel comparison tool so you can further narrow down your choices.
We would like to add that this guide and the endurance fuel database are continually updated with new fuel options as we find them, the latest endurance fuelling research and new web app feature updates which can all help you find endurance fuels that work for you and your adventures, so make sure to sign up to the newsletter so you never miss out on future updates.
Before we get in to some potential solutions to your gut issues, come and check out our commnunity on Discord where we talk trail and ultra-marathon fuelling and races and you can add your suggestions for new web app features which can help others in the future!
Step by Step Actions To Eliminate Gut Issues
We want to give you a literal step by step process and guide so that you can eliminate every possible issue that may arise for you and your gut and as we come across potential fixes or causes of gut distress, we will continue to update this guide so it is always up to date with the latest research and findings.
I would like to point out, I am not a sports nutritionist, this guide is done through my own research as an endurance athlete on what could potentially help or eliminate gut issues and then i simply link to the objective data of endurance fuel options to show you the fuel choices available to you today that answer those specific queries we're asking.
Train Your Gut
Your digestive system can adapt to processing more fuel if trained properly, just practice consuming the same foods and fluids in training that you plan to use on race day, gradually increasing your carbohydrate intake to improve tolerance.
During training I will look at a minimum of 40g of carbohydrates an hour up to a maximum of 100g of carbs per hour. There is research showing that upwards of 120g of carbs per hour is possible (consuming multiple carb types at the same time, such as 60g of glucose and 60g of fructose) and can help with your race and maximum efforts.
Due to this, it can get expensive fast, so you'll want cheaper sources of energy but with similar ingredients that works for you if you are going to train your gut for months in advance of your race.
This is where our carbs per dollar and price data points can help you and below we'll direct you to the endurance fuel database with the data, filters and sorting options selected to help you find fuel options that can help.
Get this result by showing the column price per 100g > then sorting the column price per 100g > then selecting the filter category by energy gels / energy powder / energy chews
If you are happy with your choice of gel, powder or chew, simply look at the main ingredients and carb types that it uses and find something similar that is cheaper using the links above.
Reduce or Eliminate Fructose
Some carbs digest easier than others and maltodextrin and glucose are well-tolerated by most, while fructose can cause issues for some due to its slower absorption. If you experience bloating, cramps, or diarrhea, try reducing or eliminating fructose from your fuelling strategy.
Here we have linked to the database to show gels, powders and energy chews that are without fructose. Consider further refining the database to narrow down any more specifics you may want, such as flavour, price and so on.
I get to these results by selecting category energy gels / powders / chews > filtering by without sugar fructose / naturally present sugar / fruit juice concentrate
Adjust Carb Ratio (Glucose:Fructose Balance)
If you are having no luck with completely removing fructose from your fuelling choices, then try a more refined ratio of glucose to fructose.
According to current research, the best carb ratio of glucose to fructose for ultra marathons is 1:0.8 (glucose to fructose), meaning for every gram of glucose, you should consume 0.8 grams of fructose; this ratio maximizes carbohydrate absorption and minimizes digestive issues during endurance feats.
We are currently adding carbohydrate ratios to the endurance fuel database and each and every single gel, powder and chew that we add to the site. This feature is coming soon, sign up to the newsletter so that you are updated as to when we add this and other new features to the web apps.
Try A Lower Carbohydrate Intake
Look for less carbs and more calories as overloading carbs can cause bloating. Below we look at fuels choices by carbs per 100g so that you can test lower amounts of carbs in your fuel choice.
I got this result by filtering the category energy gels > then sorting the column carbs per 100g
Increase Electrolytes
An imbalance in sodium intake can cause bloating, nausea, or dizziness. Too much salt can lead to dehydration if not balanced with enough water, while too little can result in cramps and GI issues. Track your sweat rate when you are moving, how wet is the back of your t-shirt against your pack, are your lips dry, use these as indicators and adjust your sodium intake accordingly.
As well as filtering and sorting the data you can also add new data columns to the table by going to the top of the table and you will see a box with Show/Hide Data and here you can hold ctrl+select the extra data columns you want to see.
Below I have added the electrolytes amount which will show you how many electrolytes are contained in the endurance fuel, if it has sodium and calcium, it has 2, if potassium is present as well, that is 3 and so on. Then I also added electrolytes data column which shows us the actual electrolytes used in that fuel.
Next we look just at the amount of sodium in each endurance fuel.
If you prefer energy powders
- Energy powders with the most sodium per 100g
- Energy powders with zero sodium or electrolytes aren't in the database yet, but make sure to sign up to the newsletter as we are always adding new fuels and we could add an energy powder with no electrolytes in the near future!
- Energy powders with the least sodium per 100g
If you prefer to chew your energy and fuel options, here are
- Energy chews with the most sodium per 100g
- Energy chews with zero sodium or electrolytes don't seem to exist yet in our database but here are a list of energy chews with the least amount of sodium
I got the results above by adding the column and data point sodium per 100g > then filtering by energy gels > then
Use Ginger for Gut Relief
Ginger can aid digestion and has been shown to ease nausea and bloating, there are some new energy sources coming to market which contain ginger in them and below we link to gels, chews and powders that contain the stimulant ginger.
Some research also shows that peppermint can help, but we are yet to add any endurance fuel options with peppermint in them, when we do we will update this section.
Avoid Artificial Sweeteners and Try Wholefoods and Minimally Processed Fuel Options
Certain artificial sweeteners like sorbitol and sucralose in sports drinks and endurance fuels can trigger gut issues. If you suspect these are causing trouble, switch to more natural ingredients or whole-food-based fuelling options.
We are currently adding a sweetener category to the fuel database and individual fuelling options so this feature is coming soon.
Maybe consider not taking processed energy gels, chews or powders at all but instead try wholefood sources of energy, like Luchos Guava Energy Chews.
I get to these results by filtering the category by energy gels / energy chews > ingredients composition by wholefoods
You can also look in to fuel options that have the least amount of ingredients, this might help with narrowing down issues that may be arising through a particular ingredient. If a fuel option has less ingredients you may have more luck with it working for your adventures and races.
I got this result by selecting amount of ingredients in the Show/Hide data column feature > then sorted by the column in ascending order.
Choose Lower Osmolality Fuels
A lower osmolality energy gel, chew, or powder is typically maltodextrin-based instead of simple sugars like fructose or glucose. Maltodextrin has a lower osmolality because it consists of longer-chain carbohydrates and should help avoid stomach issues. Try diluting drinks and energy powders slightly more than you would or spacing out gel intake with small sips of water rather than consuming large amounts at once.
I got to this result by filtering the category by energy gels / powders > energy sources by single energy source > sugar type by maltodextrin
Reduce Fat and Fiber
High fiber or fatty foods can slow digestion, leading to bloating or urgently requiring the toilet during your race. Stick to low fiber, low-fat meals in the 24 hours before your event to keep your gut running smoothly.
If you were wondering about fiber or fat in endurance fuels, you can show the extra columns fiber per 100g and fats per 100g and sort by them to check the fuel options you are interested in are low fiber and fat.
Switch Texture or State of Fuel
Some runners digest liquids or chews better than solids. Compare fuel types to test different formats.
Some runners tolerate drinks better than gels or chews, while others struggle with solid foods late in a race. Experiment with different forms of fuel (liquid, gel, chew, or whole foods) to find what sits best in your stomach.
To get this result you just have to use the facet gel consistency and select one of the three options, thing watery gel, medium syrupy gel or thick firm gel.
Space Out Your Fuel Intake
Consuming too much too fast can overwhelm the gut, you should consider eating every 15 minutes instead of every 30 minutes and choose slower released energy sources.
By spacing out your fuel intake you give your gut a bit more time to manage the fuel you are putting in, rather than dumping in a massive gel less frequently.
This might be as simple as sticking with the fuel choice you already use or looking at an endurance fuel option that has less carbs.
Stop Taking Caffeine or Other Stimulants
Caffeine can irritate the gut, if you're taking caffeine in your gels then consider stopping this. Below we filter for caffeine-free options for you to test.
I get these results by using the stimulant filter and selecting none, then selecting the category type of fuel of energy gels, energy chews, energy powders.
Test Multiple Brands And Suggestions Together
Some formulas just don’t work for certain people, explore alternative brands in the database to find a better match.
As you are using the database, remember that you can continually filter and sort to your hearts content. Above we have filtered and sorted only once or twice per issue, to remove fructose we simply filtered to show gels that have no fructose. But what if you want to test multiple suggestions at once, you can do this.
You can filter to show energy gels with no fructose but also sort the data to show gels that have the most calories but the least carbs, this covers a couple of the suggestions in this guide at the same time and it may be this combination that works for you.
This filtering feature is like feeding two birds one scone, rather than just eliminating one thing at a time.
There are literally thousands of combinations and fuel answers to be found using the endurance fuel database and don't forget that you can also compare up to 4 fuel options side by side by selecting the compare this product which is the last column in the table and then selecting up to three more options to see their data side by side.
And if you have any suggestions for fixing gut issues then we would love to hear in our Find Trail community over on Discord.