Here’s Why the ‘Fat Burning Zone’ is a Myth

Do you workout in your ‘fat burning zone’? The fat burning zone is the idea – and myth – that in order to burn fat as you exercise, you need to exercise for a long time all at once – and slowly.

This, of course, goes completely against the ideology of high intensity interval training (HIIT) and high intensity stimulation training (HIST) – working out for shorter periods of time, but at a much higher intensity, for greater physical benefits.

Experts who praise this myth aren’t completely wrong – there’s some science to back up why this myth might work in theory. Looking closer, though, it becomes pretty clear how little sense it makes. Here’s why.


The fat burning zone isn’t a myth in the sense that it does not exist. Technically, at a certain intensity level during physical activity, you burn more calories from fat than from carbohydrates. So it’s understandable why you might jump to the conclusion that burning more calories from fat equals more fat loss.

You have to look at the big picture, though. The belief that there is a specific “zone” most ideal for burning fat is based on percentage of calories burned related to your heart rate. However, you don’t just eat and burn off only fat. You eat carbs and protein, too – which your body uses as fuel first, before it even touches your fat stores.


Recent research tells us that a hormone called irisin is responsible for converting stored fat into calorie-burning fuel. Fat loss happens when your body starts to “burn off” more of the fat stored in your cells than you’re putting into your body.

But before your body burns off fat, it first has to handle the fuel you get from carbs. This is why a diet higher in fat and lower in refined carbs isn’t as bad as it sounds. What your body doesn’t use calorie-wise, it stores as fat. To start burning off your energy stores, you need to, in a sense, use up your energy from carbs as quickly as you can. Hence, HIIT.


The idea of the fat burning zone makes it seem like not working as hard somehow helps you burn more calories. Not quite. Because your body uses carbs as energy first, you need to do a workout that burns through your calories from carbs – which is what happens at a higher intensity training.

While it may be true that you do technically burn more calories from fat during a lower-intensity workout, overall, you burn more calories during a HIIT workout – even though it’s usually shorter. If your goal is to lose fat, you want to burn calories from all macros, not just fat, in a shorter period of time.


Burning off excess fat is dependent on a combination of intense (but safe) training, proper nutrition and plenty of rest. Here are a few things to remember to achieve optimal fat loss:

  • Switch up your workouts so you’re working out your full body – such as interval training one day and some endurance training the next. Your body burns fat all over your body, so to lower your body fat, it’s best to keep consistent, but vary your activities.
  • Eat fatty foods. No, really. Fish, dairy and nuts are all perfect examples of unsaturated fats that actually promote fat burning. Don’t just pile on the protein and carbs – remember, your fat stores are your body’s last resort when it comes to fuel.
  • Get enough sleep. Sleep deprivation messes with your metabolism, making it so you generally burn fewer calories throughout the day no matter what you’re doing. Not good!

So we’ve given you yet another reason why high intensity workouts are king. Add a few to your schedule this week. Build muscle, burn fat, save more time at the gym and feel like all your efforts – and sweat – are finally paying off.

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