FatMax: definition, training (zone) and exercise test

Whether you like cycling, running or any other endurance exercise: knowing your FatMax zone will enable you to train your fat oxidation and boost your endurance performance. This blog contains everything you need to know about FatMax. From theory to practical application. Let’s dive right into it!


FatMax is the maximum amount of fat that an athlete can “burn” per hour. It is often expressed in energy (kcal) per hour. FatMax is also a training intensity: the intensity at which you burn the highest amount of fat.

The FatMax can differ vastly from one athlete to another. Important factors that together have a huge influence on the FatMax are: VO2max, VLamax and body composition.

When looking at an individual athlete, the fat burning rate (or better: fat oxidation rate) depends on the exercise intensity.

  • At low intensities you will not burn a lot of fat, since you don’t burn that much energy at all.
  • When intensity increases, fat oxidation increases as well. But only up to a point (= FatMax).
  • At very high intensities, you will not burn any fat.

As a result, you get a concave (upward; n-shaped) parabola:

FatMax infographic


In endurance sports like (marathon) running, triathlons, open water swimming and cycling, a high FatMax is associated with a high performance. That is because using fat as a fuel saves carbohydrate stores (glycogen).

Saving carbohydrate stores ensures you don’t run out of glycogen unnecessarily fast. That is a good thing, since once you do run out of glycogen, fatigue will develop quickly. In other words: burning more fat during endurance events delays fatigue.

Watch the video to learn more about fat and carbohydrate combustion:

How to increase fat combustion (FatMax)

We collected the 3 best training tips to increase fat combustion. Two of them will increase fat combustion immediately and one will increase FatMax over time. We’ll dive into training and nutrition.

Get 3 tips on how to increase your fat combustion via our free whitepaper:


Knowing the importance of FatMax and the fact that the maximal fat metabolism is highly individual, leaves us with the question: how can you determine FatMax? The determination of FatMax is done via a FatMax test.

When using the INSCYD software, your have multiple options when it comes to testing. You can do a lactate (field) test, a spirometry (lab) test, a test that only requires power (cycling) or GPS (running), or a combination of the above. All tests will give you an accurate FatMax and FatMax intensity.


Athletes can easily find an INSCYD coach and perform a (remote) FatMax test. Coaches can become an INSCYD coach, test and discover the FatMax of their athletes and create the best FatMax trainingplan. Start now!


After performing an exercise test, the INSCYD software creates your individual fat combustion graph. You now know exactly how much fat you burn at any given exercise intensity. You also know your FatMax (kcal/h) and FatMax intensity (e.g., speed or pace in running and swimming; power in cycling).

Fat & carbohydrate combustion graph
The green line shows the fat combustion rate. The FatMax is 504 kcal/h (y-axis) and occurs at a FatMax intensity of 214 watt (x-axis). The vertical shaded zone is the FatMax zone (+/- 10% of FatMax intensity).

INSCYD also offers you an individual FatMax training zone, which is also known as “zone 2” for improving mitochondrial functioning. This training zones is +/- 10% of the FatMax intensity. Ride/run/swim/exercise in this FatMax zone and you are sure you’ll burn the most fat. Knowing the FatMax zone allows you to train fat combustion more efficiently.

FatMax training zone
FatMax training zone INSCYD

What is a good FatMax?

This scientific paper shows that on average, in a group of 300 healthy men and women, the highest individual fat oxidation (FatMax) equals 27.6 grams of fat per hour (range: 10.8 – 60.6). This equals 248 kcal/h (range: 97 – 545).

To give you an idea about the training level of the group: average VO2max was 46.3 ml/kg/min.

On average, FatMax occurred at an exercise intensity of 48% of VO2max (range: 25 – 77). This was equivalent to 62% of max heart rate (range: 41 – 91).

Notice the wide ranges in FatMax and FatMax intensity? This means that you can use these comparison numbers to compare with your own FatMax, but you cannot use the comparison group data as a guideline for your own training.

Men had a significantly lower FatMax than women at a significantly lower exercise intensity.

Average FatMax men: 0.44 grams of fat per kg fat free mass per hour, occuring at 45% of VO2max. This equals 4.0 kcal/FFM/h. Their average VO2max was 50.7 ml/kg/min.

Average FatMax women: 0.50 grams of fat per kg fat free mass per hour, occuring at 52% of VO2max. This equals 4.5 kcal/FFM/h. Their average VO2max was 41.4 ml/kg/min.

You can find your fat free mass (FFM) in the INSCYD report.

In a scientific research with more well-trained athletes (N=18, average VO2max=58.4 ml/kg/min), the average FatMax equaled 36 grams of fat per hour (324 kcal/h). The FatMax intensity was 64% of VO2max, again with a wide range: 42 – 84% of VO2max.

Use this normative FatMax data to compare with your own FatMax and to understand what to work on to get the ideal metabolic profile, depending on your goal.


Enough about the theory. It’s time to increase FatMax by training! Here are the three most important rules to follow for increasing fat oxidation rates. The whitepaper discusses both the training aspect as the nutrition aspect. No pseudoscience – just clear physiological facts…steeped in science.

If you coach or lab and you are not sure how to apply FatMax to your training or lab setup? Schedule a free 1:1 consultation with our INSCYD team, available in your own language! We’ll help you get the most out of FatMax for optimal endurance performance. Book your consultation now!

For coaches and labs

Watch Inscyd in action

With INSCYD, you can tailor training programs with unparalleled precision, ensuring your athletes achieve their peak performance faster and more efficiently.

Don’t let your athletes settle for anything less than their absolute best. Book a Free Demo with INSCYD today and experience firsthand how you can elevate your coaching game.



Athletes why train with generic plans when you can have a program tailored to your unique physiology? INSCYD is the key to unlocking your full potential. Find your dedicated INSCYD coach or lab here. 

Already have a coach? Experience INSCYD in action with your coach and redefine your training approach.

Related Posts

FatMax: definition, training (zone) and exercise test

FatMax: definition, training (zone) and exercise test Whether you like cycling, running or any other endurance exercise: knowing your FatMax zone will enable you to train your fat oxidation and boost your endurance performance. This blog contains everything you need to know about FatMax. From theory to practical application. Let’s dive right into it! WHAT…

Read more
Mark Turnbull INSCYD coach

Use case: rehabilitation program using INSCYD

James (39) is self-employed, working long hours and having to fit training in around his demanding physical job. His results had plateaued and he was finding it difficult to structure his training and balance his work/life commitments. As a result, he was struggling to improve his performance enough to warrant the time and energy necessary…

Read more

Anaerobic threshold (FTP): why you might be overthinking it

How many times have you looked at your power meter or heart rate monitor and wondered if you were going too far above your threshold? Although it is reasonable not to kill yourself ‘just because’ when you’re out training and racing, you might be surprised by how little you actually know about one of the…

Read more
Running power with Stryd and INSCYD

Running power: how to add physiological meaning to it

With the arrival of affordable running power meters like Stryd, power has become an important metric in running over the past years. Now it’s time to unlock the power of your running power meter. Previously, power was only a number expressing your output. Today INSCYD links this running power to your individual physiology. The result:…

Read more
INSCYD 2.0 Training Zone Builder

INSCYD launches a revolutionary Training Zone Builder

Are you still using training zones based on a percentage of FTP, Anaerobic threshold or fixed lactate concentrations? Do you get the feeling that two athletes training in the same zone don’t show the same adaptation to the same training? If this sounds familiar then it is time for a change! https://youtu.be/hZELSARsJtA With INSCYD’s new…

Read more