Tag Archives: fat burning zone
A discussion of the evidence put forth in parts 1 and 2 of the Myths Under the Microscope series, regarding the fat burning zone and fasted cardio myths.
The fat burning zone is a misunderstood concept. Training within this zone may actually inhibit weight loss relative to higher intensity sessions.
I was sifting through our website statistics today and I was really happy to see that an article I wrote entitled The Fat Burning Zone is one of the most popular pages on the entire website. This article was published in Australian Ironman Magazine and Fighting Fat Magazine. It discusses the fat burning zone myth; how it came about and why it is completely misguided.
I have discussed this fat burning zone myth with countless clients and other individuals who are seeking to lose weight. It often comes as a surprise that this zone is a highly ineffective way to break down fat tissue. This is completely understandable, considering the amount of misguided information that is floating around the industry.
The fat burning zone myth suggests that exercising at an intensity of between 55-65% of your maximum heart rate, you will stimulate maximal fat loss. Exercising at an easier pace will reduce the fat loss and exercising at a harder pace will also reduce fat loss, but target carbohydrate breakdown instead. This is not true.
What is true is that fat loss is going to be a function of the intensity of your workout. The harder you exercise, the more calories you will expend and the more fat you will break down. In fact, if you exercise at a high level of intensity, you will significantly increase the amount of fat burnt AFTER your workout! Yes, you can actually turn your body into a fat burning machine.
If you are interested in delving into this topic in more detail, then I recommend that you read my article, The Fat Burning Zone. We discuss exactly how this myth came about, why it is misunderstood and we also consider a handful of studies that have proven it to be incorrect.
Having said all this, I am by no means implying that low to medium intensity cardiovascular work is useless. I am a firm believer that lower intensities have their place, particularly with:
- People with injuries and/or medical concerns
- Elderly people
- Participants with low levels of fitness
- People with limited exercise experience
Whilst a lower level of exercise intensity may not maximise fat loss, there are always many other considerations to take into account apart from just "results".
When I think about the "fat burning zone", I think of wasted time, minimal results and boredom. But there is a very long-standing myth in the health, exercise and fitness industry that, sticking to the fat burning zone (which is a low-medium intensity workout) will be an optimal workout to "target" fat cells. This just isn't the case.
When considering just fat and carbs as an energy source for cardiovascular work, it is true that, as a general rule of thumb, more fat is utilised relative to carbohydrates in order to fuel your body to perform the actual cardio workout. Note the word "relative".
As you increase your level of intensity, relatively speaking, you begin to utilise more carbohydrates than fat.
But hang on a second, you are exercising more, thereby expending more calories. Therefore, even though, relatively speaking, you are using more carbs than fat as energy, in absolute values, you are actually using more carbs and more fat.
Exercising in the "fat burning zone" may be appropriate if any of the following apply to you:
- Are just beginning an exercise regime
- Have a low level of fitness
- You have an injury preventing you to exercise at a higher intensity
- You have a medical condition that does not allow you to exercise vigorously
- You are looking to enhance your endurance capacity
- You require more recovery from a demanding workout regime
If not, and you are seeking to improve your VO2Max, enhance fat loss or even induce muscle synthesis (gain), then high intensity (possibly interval) training is the way to go.
Personally I haven't exercised in the "Fat burning zone" as part of my prescribed exercise regime for about seven years (and yes it was seven years ago that I learnt about this truth).
I've breezed over a lot of explanations in this post, so for further reading check out:
For some more advanced reading I would recommend:
An advanced in-depth analysis of the ineffectiveness of the low intensity fat burning zone for weight loss. Part 1 of the Myths Under the Microscope series.