Fuelling Strategy Test
Optimise your fuelling strategy by measuring the exact number of carbohydrates your body can take on during exercise.
Fuelling Strategy Test
Optimise your fuelling strategy by measuring the exact number of carbohydrates your body can take on during exercise.
What is the Fuelling Strategy Test?
The Fuelling Strategy test is all about how you fuel your races and long rides. It seeks to find the exact ideal level of carbohydrate which you should be consuming for your races.
Most athletes need to go through a long process of trial and error, just experimenting with different levels of carbohydrates to find the mix and quantity that suits them. Some of those experiments may cause extreme gastric distress, others will just leave you feeling weak and underfuelled.
The amount of carbohydrate we absorb through our gut is the key factor here, and everyone is different. Sometimes, although you might be able to tolerate, for example, 90g/hr of carbohydrate without terrible cramps/pain/emergency toilet breaks, it might be that this is still more than your body can actually use. Leaving an amount which is sitting in your gut making you feel heavier, and lowering your performance.
The Fuelling strategy test finds out exactly the level of carbohydrate you need, and how much your body can absorb. This means that you don’t need to take more with you on your races, and it doesn’t mean you are forced to gulp down uncomfortable amounts of gels and drinks.
Over the course of a single 90-minute session, we will collect data, and collect breath samples from before and after the test to be sent away for lab analysis. Once that is back, we will be able to give you your fuelling strategy in one hit. No further experimentation required.
What is the Fuelling Strategy Test?
The Fuelling Strategy test is all about how you fuel your races and long rides. It seeks to find the exact ideal level of carbohydrate which you should be consuming for your races.
Most athletes need to go through a long process of trial and error, just experimenting with different levels of carbohydrates to find the mix and quantity that suits them. Some of those experiments may cause extreme gastric distress, others will just leave you feeling weak and underfuelled.
The amount of carbohydrate we absorb through our gut is the key factor here, and everyone is different. Sometimes, although you might be able to tolerate, for example, 90g/hr of carbohydrate without terrible cramps/pain/emergency toilet breaks, it might be that this is still more than your body can actually use. Leaving an amount which is sitting in your gut making you feel heavier, and lowering your performance.
The Fuelling strategy test finds out exactly the level of carbohydrate you need, and how much your body can absorb. This means that you don’t need to take more with you on your races, and it doesn’t mean you are forced to gulp down uncomfortable amounts of gels and drinks.
Over the course of a single 90-minute session, we will collect data, and collect breath samples from before and after the test to be sent away for lab analysis. Once that is back, we will be able to give you your fuelling strategy in one hit. No further experimentation required.
How does a fuelling strategy test work?
In order to prepare for the Fuelling Strategy test you will need to eliminate certain foods from your diet for 48 hours beforehand. The list is relatively extensive, but essentially eliminates key sources of Carbon-13 from your diet. This will mean no gels or sports drinks, and no corn-containing or pineapple-containing foods, amongst others. Please see the full list below for details.
On the day, you will come into the lab, and we will get you to give a breath sample into a test tube. We will then fix you up to cycle or run for 90 minutes. The exercise will be at a low/moderate zone 2 level. At 0, 30, 60, and 90 minutes we will hook you up to the metabolic cart to take readings of your breathing and Oxygen and Carbon Dioxide readings.
You will also be consuming a specially prepared drink which is high in carbon-13 (Informed Sport batch tested) at regular intervals.
At the end of the exercise period we will take some more breath samples for the test tubes to be sent away, and the test is over. The whole process will take approximately 2 hours.
When will I get the results of my test?
Your results will take approximately a week to process. Then, you’ll receive a full report via email detailing your precise carbohydrate fuelling requirements.
Who should do a fuelling strategy test?
- Endurance athletes
- Long distance runners, cyclists, swimmers
- Anyone planning to complete a marathon or long event
- Anyone who regularly engages in exercise for 2+ hours
Anyone who falls into these categories will need to take on carbohydrates during exercise to perform optimally.
If this is you, then the Fuelling Strategy test can help avoid needless trial and error, ensuring you get your fuelling strategy right from Day 1.
Alongside the fuelling strategy test, you may want to try our Hydration Sweat Test to get your total fuelling and hydration strategy in one appointment.
We would also recommend all endurance athletes complete a VO2 Max test, however this should be completed on a different day to the fuelling strategy test.
Why would I want to do a fuelling strategy test?
Optimise your marathon fuel strategy, triathlon fuel strategy, or race fuel strategy in a single, 90-minute session.
Having an appropriate fuelling strategy is essential to achieving optimum race performance. The Fuelling Strategy test saves you hundreds of hours of fuelling experimentation, allowing you to get your fuel strategy 100% right from Day 1.
The science of fuel testing for athletes
When you exercise, your body uses carbohydrates as one of its main sources of fuel. Some of these come from within — stored in your muscles and liver — and others come from the food or drink you consume before or during activity. The Fuelling Strategy test is an Exogenous Carbohydrate Oxidation Test that helps us understand how well your body uses the external (exogenous) carbs you ingest — like energy drinks or gels — during exercise.
Why does this matter? Because not everyone uses ingested carbs in the same way. Some people can absorb and burn through them quickly, which helps power longer or more intense workouts. Others may struggle to process large amounts, leading to energy crashes or stomach issues.
Our fuel strategy test works by using a safe and natural form of carbohydrate that contains a special type of carbon (called carbon-13). When you consume this carb mix and begin exercising, we measure the air you breathe out to see how much of that labeled carbon shows up in your exhaled CO₂. That tells us exactly how much of the drink or gel you’re actually using as fuel during your workout.
We collect this data while you perform a controlled exercise session (usually at a moderate effort), and then use highly sensitive equipment to analyze the carbon content of your breath. From this, we can tell:
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How efficiently your body absorbs and uses ingested carbs
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What your personal fuel limit is — the point where taking in more carbs won’t help and could even cause discomfort
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How your body responds to different carb blends (like glucose-only vs glucose + fructose)
This is especially useful for endurance athletes and fitness enthusiasts looking to maximise performance without trial and error. It allows us to create a custom fueling strategy that’s tailored to your unique physiology — ensuring you get the right amount and type of carbohydrate for your sport, duration, and body.
In short: this test takes the guesswork out of fueling. With a few breath samples and some smart science, we give you clear answers about how to fuel better, recover faster, and perform at your best — no guesswork, no gut issues, just personalised data you can trust.
How to prepare for a fuelling strategy test
Proper preparation is key to a successful fuelling test. Sticking to these restrictions for at least 36-48 hours before your test will give you the most accurate and actionable results.
These dietary restrictions are essential because many of these foods can interfere with the measurements taken during the test, leading to less accurate results.
Additional Instructions
● The amount of carbohydrates you oxidise during exercise is, in part, determined by the amount of glycogen stored in your muscles. It is therefore recommended that you consume a high carbohydrate diet the day before your testing, or replicate your typical intake before races.
● Please record everything you eat the day before your first test and replicate this exact diet before subsequent tests
● Maintain your normal training routine, but avoid strenuous exercise for 24 hours before each test
● Stay well-hydrated in the days leading up to the test
● Get adequate sleep (7-8 hours) the night before testing
Dietary Restrictions
Please avoid these foods for at least 48 hours before your test:
Sports products:
● High carbohydrate sports drinks
● High carbohydrate sports gels
● High carbohydrate sports chews
● Sports products containing maltodextrin and/or fructose
Meat and fish:
● Corn fed chicken
● Haddock
● Prawns
● Trout
● Tuna (tinned, in brine)
● Whiting (smoked)
Fruit and Vegetables:
● Corn and corn products
● Quorn
● Pineapple
Beverages:
● Brewed drinks (beers)
● Carbonated drinks
Readymade foods:
● Tinned soup
● Pasta sauces
● Worcester sauce
● Mayonnaise
● Tomato ketchup
● Precooked frozen meals
Cereal/breads:
● Cornflakes
● Corn tortilla
● Any other corn-based cereal or bread
● Pastries
Additional foods to avoid 24 hours before your test:
● Alcohol and caffeine
● Fiber supplements
How much does the Fuelling Strategy Test cost?
The test, including the emailed report, costs £499. The fuel strategy test can be booked here.
What does the test cost include?
Conducting the test in our London or Manchester lab
Emailed report with personalised carbohydrate intake recommendations for competition
Benefits of fuelling strategy testing for athletes
Improve performance
Identify actual fuelling needs
Save time
Reduce risk of adverse gastro-intestinal ‘events’
How long does a fuelling strategy test take?
The fuelling strategy test takes approximately 2 hours in total to complete.
Will I need to re-test?
Generally speaking, no. If you decide that your body’s personal fuel quantity can be improved by ‘training the gut’ to take on more fuel, and then you engage in this over a long period, there might be a case to take a second test to see if you’ve managed to improve. Otherwise, you’ll only need to complete this test once.
How long does it take to get my fuelling strategy test results?
We will email your results through to you approximately 8 days after your appointment. This is the time it takes for the breath samples to be sent away and analysed, and a report prepared.
How can I use my fuelling strategy test results?
The results will give you a clear figure in grams of carbohydrate per hour that you should hit when in your races. Once you have the figure, you can hit the streets and try it out to see how you feel about the levels we’ve measured.
Do I need to exercise during the fuelling strategy test?
Yes, you will need to exercise at a Zone 2 level for 90 minutes. This can be done on our treadmill or watt bike.
How should I prepare for the test?
Please see the detailed instructions above for dietary restrictions and other pre-test preparation you should complete.
Can I discuss my results with the consultant?
Your results will not be available on the day. After we have received your results back from the lab, we can discuss your results with you over the phone.
Will it hurt and does it involve needles?
No, the test won’t hurt, and it doesn’t require any needles. You will need to complete 90 minutes of zone 2 exercise while wearing a mask to measure your carbon dioxide and oxygen levels.
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