How To Recognize Fat Burning Metabolism vs Sugar

How To Recognize Fat Burning Metabolism vs Sugar

Check out this excellent tutorial on fat burning metabolism via video and transcript from Tim Barnes and the team at M360 Clinical Fitness.  It’s a case study in learning what fat burning and sugar burning looks like in metabolic testing.  You can learn not only the measurements with the PNOE Metabolic Analzyer that allow you to see how your body or your clients’ bodies use fat and carbohydrates, but also how to take the next steps to change from sugar burning to fat burning.


Hello and welcome to M360 clinical fitness!

Today we are going to be talking about the process called cardio-metabolic crossover where our metabolism shifts from using fat to sugar as a fuel. 

We want fat oxidation to pay to bulk of the bill for anything we doing. 


It is more efficient and effective, it reduces inflammation, and it’s less of the oxidative stress that leads to chronic conditions and chronic diseases. 

So today we are going to see optimal and a less than optimal result as a result of cardio pulmonary exercise testing at M360 Clinical Fitness. 

So stay tuned and absorb all you can, my friend.

Data From The PNOE Metabolic Analyzer

(Note: Using the PNOE Metabolic Analyzer for recording and seeing the cardio-metabolic data)

Fat Burning Metabolism

Here is an example of a good cardio-metabolic crossover.

As you can see, there is a distinct crossover of the yellow (fat) and purple (sugar) where the lower intensity is funded by fat. 

Sugar and Carbohydrate Burning Metabolism

Here is a less than optimal cardio metabolic crossover.

As you see the crossover of yellow (fat) and purple (sugar) happens far to the left about 15% versus 85% on the other. 

We are going to go over these details. 

2 Cases of Cardio-Metabolic Crossover

Today we are going to talk about the Yin-Yang of cardio-metabolic crossover. 

It is very simple, and near and dear to our program in M360 Clinical Fitness.  It is the basis for understanding that your fat mass, your lean mass, your athletic ability, your athletic performance and your human performance are all what I consider an endurance sport, and that is your life. 

Let me just point out what these colors mean. 

It’s very, very simple. You see the color code at the top left. 

Fat, carbohydrate or sugar, wattage (that’s the power performed on this test) and heart rate.  

Fat Adapted Cardio-Metabolic Crossover

This test is with me by the way. 

Real simple test (using a stationary bike to record power and the PNOE Metabolic Analyzer for the metabolic data):  I started with 50 watts on the stationary bike and every three minutes I went up 25 watts, using 11 3-minute steps, and I actually did the last three minutes at 312 watts. 

So I brought my heart rate up to about 90-95% of my maximum heart rate.  You can see that I had achieved cardio-metabolic crossover (where the yellow and purple lines cross) between 85-88% of my max heart rate. 

The purple line down here is my Sugar – Carbohydrate. 

You see it comes out strong right at the beginning and then fades away, and that’s what is called a glycogen or glucose burst.

It is common to any and all activity that when you start anything this miraculous body we have jumps into gear in fight or flight mode.  Glycogen (Sugar / Carbohydrate) is our body’s established energy source for us to do what it is we do quickly in fight or flight.  As we go on with that activity that source goes down as we relax and the nervous system calms down.  Then the magic of fat comes in which is a very, very economical and efficient fuel.  It makes over twice the amount of energy, three times the amount of energy actually.  Its one hundred and nine versus sugar at about 36. 

So fat is a far more efficient, far more effective source of fuel. 

So to see lower intensity activities the green line is the wattage and my effort so you see it starts at 50 and then goes up. I was having hard time it keeping it as low as 50 in the very beginning but then it kind of leveled and I was able to keep the watts all the way up.

So what’s important for you to understand is the intensity goes from low to about as high as I can go.

For the heart rate this purple line here goes from lowest up to my max on this given day.  My VO2max ended at around 60 millilitres per minute per kilogram. 

That puts my VO2max around 63. I am 60 years old so that’s pretty good. 

So as power come up that intensity goes from low to high. 

The Metabolic Bill: Fat vs Sugar

Who pays the metabolic bill? 

Well a good example here is fat.  If you have a metabolism that does not act similarly, then you going to have trouble removing fat from your body. 

You are going to constantly going to programs like Weight Watchers. 

You will be calling on Marie Osmond to send you dinner to your mailbox. 

That stuff never work over the long haul. 

So what you want to do is you want to get your metabolism working for you rather than against you. 

You will have more energy, more power, better human performance, less inflammation, less oxidative stress, less fat mass and less chronic conditions that lead to the bulk of our health costs in this country.  That’s is chronic disease. 

Remember that of 3.2 total health care dollars 2.9 of it is being spent on chronic disease. 

So we want to target chronic conditions that lead to chronic disease. At and this very basic level if your metabolism doesn’t reflect a high percentage use of body fat for fuel then you are going to have problems. 

That’s my take, and I am sticking to it. 

Sugar Adapted Cardio-Metabolic Crossover

Stay tuned we are going to go into the next less than optimal example that I will point out and then you will have an opportunity to act on this data.

Here we are with a less than optimal CPET (Cardio Pulmonary Exercise Test) test for cardio-metabolic fitness and cardio-metabolic crossover. 

Remember we want that crossover to happen at the highest workload or heart rate that we possibly can because we want fat to pay the metabolic bill. 

If you are having trouble losing body fat, reducing your fat mass and improving your composition then most likely your metabolic crossover test is going to resemble this one.  

You can see the purple is sugar, the yellow is fat, the green is your watts. 

This persons protocol took them from 35 watts and you can see the yellow peeking out at 50 to 75. 

Heart rate went from about 85 beats a minute up to 200 beats per minute. 

So they did an excellent test. 

The problem with this profile is very little fat adaption. You can see that this metabolism leans on sugar for the primary substrate for ATP (Adenosine Triphosphate), the currency of the human body in terms of energy. 

So life is an endurance sport and you just simply cannot spend this kind of energy for the long term.  You are going to deplete the glycogen stores and then create carbohydrate craving.  You will not be releasing or letting go of body fat plus your insulin levels will be high. 

So all kind of negative things that come from this. 

We want to simply take this person and improve their ability to utilize fat for fuel or make them fat adapted versus sugar addicted.

Learn More About Fat Adaptation

Please find out our book at Barnes & Noble online, or in stores and booksellers worldwide and you can get started on a path towards fat adaption. 

I would also recommend Dr. McCullough’s Fat for Fuel or you can give us a call at 719-289-0351.

Thank you and have a great day. 

Learn more about M360 Clinical Fitness at

(content provided by Tim Barnes and M360 Clinical Fitness

Interested in using the PNOE Metabolic Analzyer for your own business or personal use, to measure and analyze metabolism?