Debunking the "FAT BURNING ZONE" Myth - Personal Trainer Community - Forum

[muscletrainerdh-NSCA CPT]

So many of my clients and fitness center members think that if they exercise at a lower intensity pace that it burns more fat and will make them thinner.

I found a couple of explanations debunking this myth and this table

45 Min of Exercise at 65% MHR
Calories Burned: 213
Fuel from Fat: 85%
Fuel from Carbs: 15%
Fat Loss: 20g

45 Min of Exercise at 85% MHR
Calories Burned: 555
Fuel from Fat: 30%
Fuel from Carbs: 70%
Fat Loss: 18.5g

To which I add: The same amount of exercise time at a higher intensity burns more than two times the calories. It is this burning of extra calories that will lead to greater fat loss regardless of the percentage of fat used as fuel.

But won't clients and members see the 1.5 grams greater fat loss of the low intensity and still think it's more beneficial to exercise in the "Fat Burning Zone"?

What do you use to debunk the Fat Burning Zone myth?

[Joe Cannon MS CSCS]

When I certify personal trainers one of the first things I try to debunk is that "fat burning zone"

As you rightly pointed out, at lower intensities we burn a greater percentage of our calories from fat. If we take that reasoning (low intensity burns more fat) to its ultimate conclusion, sleeping burns the most fat! in fact about 70% of the calories that keep us alive when we sleep are coming from fat. So, the question I usually ask is why people don’t get skinny sleeping? The answer, as we know, is that we don’t burn many calories when sleeping. Exercise burns more calories and calories -not how much fat is being used - is the key to weight loss.


The fat burn program that is on treadmills etc has its place because it lets novices exercise at a low intensity. Low intensity = lower risk of injury, which is great for novices.
Joe

[GFitness]

What I've heard about the fat burning zone is that it is more effective (in regards to fat loss) to exercise at a lower intensity for a significantly longer period of time.

In the chart, even at equal duration workouts, the low intensity trainer is burning approx. 20 more calories from fat than the high intensity trainer. If you extend the workout, this fat calorie total will be higher, and the calorie total overall will near that of the higher trainer.

It seems to me (and this may be mislead, of course) that when a person is burning calories from carbohydrates, the bulk of their energy is coming from reserves in the liver and possibly small stores in the muscle tissue itself. This seems not to be directly related to fat loss, whereas calories from adipose tissue is directly related.

Are there flaws in this idea?