The fat burning zone was quite a myth.

One that lasted for too many years. It’s based on a concept that you should keep your workout at a very low intensity so you will burn more fat and less sugar when you exercise. You’ll still find the “fat burning zone” on heart rate graphs and charts posted in  gyms and on the cardio machines.

I never advocated a workout based on the “fat burning zone”.

Very low-intensity exercise does not burn the number of calories most people need to burn in order to lose weight efficiently, nor does it improve the function of heart, lungs and blood vessels in a big way.

The “fat burning zone” concept was propagated by media

and, believe it or not, cardiovascular machine manufacturers. I don’t think they did it on purpose, it was most likely a misunderstanding of the whole picture on how our body burns calories. But even with today’s shift to the newest exercise trend, high intensity training, it’s still important for you to know the fundamentals of how the body burns fuel so you can make intelligent choices for yourself – and not be led astray.

Our bodies are constantly burning a blend of both fat and carbohydrate.

When we’re hardly moving (like sleeping or sitting on the couch) we’re burning a higher percentage of fat because fat is our body’s slow-burning fuel. We’re also burning very few calories during any given minute.
As we increase the intensity of our movement (like walking around the block) we’ll start to burn a greater percentage of glucose (sugar) from our blood and glycogen (long chains of glucose) stored in our muscle. We’re also burning fat, but at a lower percentage, and we burn more overall calories per minute.
If you take it up a notch more and run around the block, an even greater amount of blood glucose and muscle glycogen is used, because glucose is a readily available and fast-burning fuel. You’re still burning some fat, and you’ll burn even more calories per minute than if you were walking.
After the fuel (glucose) is used from your blood and muscle, the body needs to take fuel from reserves (fat) to replenish your blood, muscles and brain with the energy it needs. You also need to eat some back.

Fat loss occurs

when you burn an excess number of calories for days, weeks and months and your body uses up fuel from your fat stores.

  • Since higher intensity workouts help to burn more total calories in less time, more body fat will ultimately be used as fuel in the long run.
  • Higher intensity workouts improve the oxygenative systems in your body. That means your body becomes more efficient in using oxygen (which is essential for burning fuel) which means you become a better fuel-burning machine (more efficient at burning fat, sugar and calories).
  • So, even though you burn a greater percentage of calories from fat on lower intensity levels of movement, you burn more calories overall when you work harder. Therefore it’s more effective for weight loss to work harder during a workout. It’ll also push you further in your quest for total health.

So now, the fat burning zone is out, and High Intensity Interval Training is all the rage.

Do you think the media is perpetuating some myths about high intensity training, too? You bet it is. My next post talks about how to realistically look at high intensity interval training, and how hard you really need to work if you want to burn twenty-minute’s worth of calories and get an hour’s worth of cardiovascular benefits, in 4 minutes.

It’s terrible that so many people were roped into

the belief that they needed to purposefully keep their workout intensity down in order to lose body fat when they could’ve gotten much more bang for their buck out of the time they spent at the gym. Although all of my clients knew the fat-burning zone was a myth, I could only tell so many people in person. I started this blog so I could help more people get the most out of the effort they put into having better health- and live in a healthy, happy, balanced way. If you want my continuing advice about how to live a balanced and optimally healthy life, subscribe here.

This is the first of three articles

on the hype and reality of high intensity interval training. Read the second article here.

For More Guidance and Personal Attention

on how to build healthy lifestyle habits that last – including ramping up your exercise in a safe and efficient way – join me at Mind Body Blast  It’s a budget-friendly online class with lots of personal attention from me and tons of group support. We’re opening the doors again soon, and I’d love for you to be there.

For further reading on this topic:

Edward F. Coyle, Ph.D., Sports Science Exchange, Fat metabolism during exercise, SSE#59, Volume 8 (1995), Number 6  –

Science Daily, Interval Training Burns More Fat, Increases Fitness, Study Finds –

Gibala MJ1, Little JP, Macdonald MJ, Hawley JA., Physiological adaptations to low-volume, high-intensity interval training in health and disease.  J Physiol. 2012 Mar 1;590(Pt 5):1077-84 –

More here.