Fat Burning Exercise: What is the Fat Burning Zone? by Anders N W Lindgreen

The Fat Burning Zone is a misunderstood concept used to promote several fitness classes, weight loss routines and magazines. It is the perfect example of only using certain parts of a study either because you didn't bother to read the whole thing or didn't understand how to use the information within - or option three where you knew exactly what you were doing but twisted the words for your benefit. But let's imagine that no one would do such a thing, what is the go with fat burning exercise and the magical fat burning zone?

The Truth

The Fat Burning Zone is when you work to 55-65% of your maximum capacity (e.g. 110-130 beat per minute if you max heart rate is 200 beats per minute), which leaves your body burning 65% of the energy from fat and 35% from carbohydrates. This is called low intensity exercise. The other end of the spectrum is working at 80-90% of your capacity but now you only burn 50% of the energy from fat and 50% from carbohydrates. This is called high intensity exercise.

Well, so far it looks like low intensity exercise burns more fat than high intensity exercise and this is also where most people stopped reading. What they didn't read is that when you work at a higher capacity your burn more energy over the same period of time, even if the percentage of fat is less. So what does this mean?

High intensity Burns More Fat Overall (and then some!)

Let's say for arguments sake that 30 minutes of low intensity exercise for a given activity would 250 calories, 162.5 of them would come from fat (65%). Working at 80-90% will many times almost double your energy consumption and 30 minutes would burn off 500 kcal, where 250 comes from fat. In reality, high intensity exercise burns more energy overall AND more fat. But it doesn't stop there.

High intensity exercise creates something called an oxygen deficit in our bodies, which can boost our fat burning capabilities for up to 36h. That is during rest AND activity. But that is not all. Burning through your carbohydrates is by no means a waste of time, because when you run out of your stores your body goes straight for the fat. So burning through your carbohydrate stores faster will also have you burning more fat.

Try It For Yourself

Even though I've used nice and round numbers to make it easier to understand you can Google for a site called "Calories Per Hour", choose your activity, put your own numbers in and see the difference for yourself. But hopefully you can now see that staying in the fat burning zone doesn't necessarily burn more fat.