FatMax The Optimal Fat Burning Intensity

cardio training

Many trainers make the mistake of categorizing all aerobic training into one heading “cardio” and often set workouts without thought to which energy source the body will elect as fuel and at which pace exactly we should train at.

However an efficient cardio session will account and factor for several key variables and stimuli that must be employed to ensure the training target is met.

If we wish to use our fat to fuel our cardio session (fat oxidation) then we need to deplete insulin (no sugar/carb ingestion 3hrs +) and train at the correct intensity.  There are many opinions on LISS and SS but unless you are a beginner or recovering from injury the volume required at this intensity defeats logic.  You will also in most cases omit all cardiovascular benefits and progressive improvements compared to training at an intensity of 50% ++ Vo (2R) *ACSM , basically at SS /LISS your training intensity is  too low to induce change.


You will remember for allowing “low intensity” to slow down the fat loss process and halting fitness levels. Now Step aside for the CORRECT and most effective protocol for singular interval cardio training, Get inside the FATMAX CARDIO zone!

What I am about to tell you here has been one of my most effective secret fat loss protocols to help get my celebrity and high net worth clients into ultra lean condition for the past ten years. Needless to say I have personally adopted this protocol, and its one of the key elements to keeping my physique locked at 5% body fat year round with ease. Don’t worry if you don’t fully understand how to adopt this fat loss method, the Cardio Guru Fat Loss App has all the calculations, features and workouts built into its advanced software approach.

There is not one singular training intensity that gives the body the spectrum of stimuli needed to induce change into the adaptive pathways that force change upon our body. This “change” is how we obtain our fitness goals.

Training cardio smart to me, means balancing several protocols, i.e. HIIT  / VO2Max / Vvo2 and FatMax to give complete challenge and open all adaptive pathways to the body. One of the key considerations during exercising is to try and increase the proportion of the expended calories that are we burn to be supported from fat storage. Basically you want fat as your primary fuel source.

Fat needs a high supply of oxygen so that it can be converted into energy. Fat is the body’s preferred energy source for we have unlimited supply of oxygen in the air, and we have fat deposits throughout our body. Provided we don’t exert too hard during physical activity as to have that “ gasping for breath” feeling, then we will readily and easily use our fat as the majority component for energy. Now as we crank up the intensity of our workouts, we shift away from fat and begin to use more carbohydrate as energy and less fat.

This can be best illustrated byRomijn et al. (1995) who examined fuel utilisation during 25, 65, and 85% VO2 max of training intensity

The data here showed that:

·      Total calories utilized increased as exercise intensity increased.

·     Of those calories, total fat oxidation was highest in the 65 % V02 max condition, with no significant difference between the 25 and 85 % V02 max conditions. Of those fats utilized, the greatest amount of lipid oxidation derived from adipose tissue came from the 25 % V02 max condition, followed by the 65 % V02 max condition.


An example in real terms of these findings:

20 min workout at 25, 65, and 85% VO2 max.

Total amount of calories metabolised 100, 250, and 300 for the 25, 65, and 85% VO2 max condition

Now, to calculate the amount of fat metabolized during each session, simply multiply by the percentages listed above.


·      25% VO2 max condition, 85% of the fuel would came from fat, so 85 fat calories expended.

·      85% VO2 max condition, of the 300 calories 75 fat calories expended.

·      65% vo2 max condition, the largest fat was expended, a total of 125 fat calories .

This is 40% more total fat than both the high and low intensity condition



The above demonstrates why “LISS” has been employed by many of you in the quest to burn fat; 

less training intensity = more calories from fat.  

As highlighted in my overview, switching gears and training protocols so that fat has no where to hide, is the ideal approach to maintaining fat loss gains, and lowering intensity presents advantages. However many of you have gone too low in intensity and too high in training volume and lost all possible benefits.

Now comes in FATMAX CARDIO intensity to the rescue. 

FatMax intensity is your optimal fat burning zone. Locking into this heart rate zone enables you to be in a state of prime fat oxidation.

FATMAX CARDIO provides not only the “ ideal” training intensity for one-interval cardio sessions, but also an alternative intensity levels for HIIT for those who can’t quite push themselves to 85% of their MHR.

In this instance it acts a stepping-stone, offering fat loss advantages whilst fitness stamina builds. 

On occasions I will recommend to “lower” the HIIT intensity from 85% MHR to FATMAX even for advanced clients when the body may be struggling with recovery so rather than abort an anaerobic session, training in this zone will present advantages.


Now it’s important to note here that not only are we all very different in how the body reacts to fat loss protocols, the body also adapts.  Therefore for some of us training at higher intensity will still force the body to burn fat as the primary energy for fuel.

This can come from being fat adapted, what we have eaten that day or at what stage we are at in our life fitness journey.

Science backs the FatMax corner that there is indeed a better more efficient intensity zone than LISS for fat oxidation.  Professor Jeukendrup and his team at the university of Birmingham (Int J Sports Med 24: 603-608, 2003) looked for the first time at the relationship between fat oxidation over a wide range of training intensities. I have included the paper so you can read the findings in full, however the key findings were:


·      As highlighted by the chart below:


The point at which fat burning reaches its peak is known as FATMAX

Although more fat is burned at lower intensity than max intensity levels as per previous thinking on LISS, you will notice a kink in the graph in the grey shaded area where there is still a high level of fat calories expended, but the intensity level is higher. This means more total calories are expended within a given workout time, and a large percentage of those calories are from fat being oxidized.   


Varying training intensity

The Research suggested that the best“FAT MAX” zone is achieved at 60-63% of VO2max (approx. 75% of MHR) for fit test subjects. For less fit subjects FATMAX was best achieved at 50% of Vo2Max. This is consistent with cardio data which suggests the fitter you get , the more you teach your body to use fat as energy. Using a percentage from Vo2 max to calculate your FATMAX is advisable for as you get fitter and you push up the intensity but in proportion to the increase in fitness.