Before I can tell you why the fat burning zone is a myth, I must first explain it to you. The fat burning zone was an idea that was created many years ago, and it attempts to rationalize that you burn more calories from fat while working out at a slower, steadier pace than if you participate in high intensity workouts or cardio. Technically, this is partially true, but it is misinterpreted all the time. What is the actual truth?
You do burn more calories from fat (rather than carbohydrates) during lower intensity exercise. However, when you workout at a higher intensity, you burn more overall calories of both fat and carbohydrates. Here is a comparison of the two:
Yes, comparatively you burn more calories from fat than from carbs during slower, less intense cardio/workouts. Therefore, when it comes to the desire to lose body fat, you’ll ultimately be better off by burning more fat calories and carb calories collectively during high intensity workouts (even though over 50% of those calories are from carbs). But this doesn’t mean you need to be in an all-out sprint to get these results. High intensity is relative to the individual and his or her level of fitness in that moment. So the next time you head to do a workout and cardio, focus on getting your heart rate up and challenging your body as much as you can!