You've all seen the chart at the gym, right?  The one that indicates where your fat burning zone is in terms of your heart rate.  You want lose weight so you plug away in this very low intensity zone thinking, "yes my body is going to burn all this fat away", right? Well, not really. 

Let's take a look and examine why this has become myth.  Fact: Your body is always burning  combination of carbohydrates and fat for fuel.  Fact:  The higher the intensity of the workout, the lower percentage of fat is utilized as your fuel source and a greater reliance on carbohydrates. Myth: Because you are burning a higher percentage of fat, you will lose more weight.  Yes you burn a higher percentage of total calories from fat at a lower intensity when compared to a higher intensity workout, but you have to ask yourself what is this is a percentage of. 

When it comes to losing weight, it's a matter of burning total calories(regardless of where they come from), not necessarily fat:carbohydrate percentages.  Here is the bottom line - If you exercise at a high intensity,  you will definitely burn more calories.  At a low intensity you will burn less calories.  Yes  the calories burned will come from a higher parentage of fat, but you still will not burn nearly as many total calories.  The result is...you do not lose as much weight because you burn less calories.

 

I'm not saying  you should do ll of your workouts at a high intensity.  In fact, there are plenty of good reasons to exercise in the so called "fat burning zone".  Recovery, teaching your body to become aerobically efficient, building volume base miles are a few reasons. 

If weight loss is your primary goal, then higher intensity workouts are what you need.  Since it would be tough to sustain a high intensity workout for the whole duration of your session, you may want to complete intervals.  Also, alternating by tough days and easy days might be an option to consider.  Beginners may want to lay a good foundation before jumping into intervals.