The Myth of the “Fat Burning Zone”

Walk into almost any gym in the country, or the world, for that matter, and you’ll see cardio equipment. Treadmills, ellipticals, stair climbers, you name it. Most of those will also have a selection of pre-loaded workouts. Scan through them and you’ll eventually see what may seem like the holy grail; The Fat Burner! All prayers answered, right? We all heard of the fat burning zone of heart rate training, so that’s what those of us looking to drop some pounds should be choosing. Or is it?

The “fat burning zone”, as most will define it, is a heart rate range in which a larger percentage of the calories we burn will be from fat. Generally, the fitness community and science will support this theory. It’s based on the fact that at higher levels of intensity, our bodies prefer to draw on carbohydrate stores as fuel. However, there is a need for an asterisk which leads to a disclaimer, something like “May not be a maximum fat burning session”. Many publications have labeled this the “myth” of the fat burning zone. It isn’t actually a myth, but possibly misleading. How so?

The “fat burning zone” is generally defined as 60-70% of one’s maximum heart rate. You could also consider this range as a 5-6 on a scale of 10. Moderate, but not intense. True, in this range, you may burn a higher percentage of calories from fat than in any other range. Why then the asterisk?

Let’s look at some simple math. Let’s assume that you did a 45 minute, moderate intensity workout, like jogging on a treadmill. If you spent the entire workout in the fat burning zone, let’s say you burned 250 calories, and 70% of those are from fat. The net is you’ve burned 175 calories from fat.

Now let’s compare that to a 45 minute HIIT workout, which burns around 600 calories. If only 50% of those calories burned are from fat, that’s still 300, so 125 more calories from fat than in the “fat burning zone”. In addition, you’ve done a much more beneficial workout as far as challenging your muscles and strengthening your cardiac system. In the second example. You may burn a lower percentage of your calories from fat, but overall you burn more because of the higher intensity.

Read about “Why Your 30 Minute Workout Isn’t Working” here.

In addition, the lower intensity, steady state workout in the fat burning range will leave your body packing in EPOC (excessive post-exercise oxygen consumption). EPOC causes your body to increase its calorie burn for up to 36 hours after the workout.


For many of us, time is one of the challenges in our fitness program. Make the most of yours by utilizing HIIT type training and enjoy the many benefits that go with it!

Jim Harris, the author, is a Master Trainer, holding multiple advanced certifications, including Nutrition and Weight Loss. He contributes to several publications, and is the Founder/Owner of Max Results Training LLC, pulse 45 Fitness and the owner of Oakwood BodyPlex and Harris Fitness Consulting LLC, along with his wife, Marian, who recently published her second book, Inhale, Exhale: Everyone Has A Story”

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