There is no doubt you've heard the term "fat burning zone" before and it's been a common topic at gyms for many years.
And for a long while, it was the thing that many of us tried to achieve; "Oh, I've got to keep my heart rate at 60% of max or I'll stop burning fat" has been overheard many, many times.
There is much confusion about this and I get questions pretty frequently about the best way to utilize the fat burning zone, what it is, and how it works.
So here it is..
What is The Fat Burning Zone?
You surely have seen a diagram like the one above, which shows us the optimal heart rate zones for specific fitness goals.
One such zone known as the "fat burning zone" is based on the principle that we burn more calories from fat versus carbohydrates when exercising at a lower heart rate.
And this is true, you actually do burn a greater percentage of calories from fat at a lower intensity, but here's the thing...it doesn't matter.
It doesn't really matter that much because the more important issue is that you want to burn more calories, not more calories from fat..
Let me explain.
If you slow things down by doing a bunch of steady state cardio (treadmill, walking, jogging, elliptical, etc), you ultimately burn fewer total calories than say using interval training, which is fast faced and gets your heart rate way up.
Here's an example:
60 minutes of low intensity exercise
- Total calories burned: 300
- Fuel mix: 50% fat, 50% carbs
- Carbs burned: 150 calories
- Fat burned: 150 calories
60 minutes of high intensity exercise
- Total calories burned: 450
- Fuel mix: 35% fat, 65% carbs
- Carbs burned: 292 calories
- Fat burned: 158 calories
As you can see, you burn a greater percentage of calories from fat during low intensity exercise, but fewer overall calories than with high intensity exercise.
Even with 65% of calories (approximate) coming from carbs, you'll burn a fewer calories from fat because the overall calorie burn is greater with high intensity exercise.
This is why HIIT type training has become uber popular over the last few years. It's because you're working at a very intense rate and burning more calories in a shorter time and creating a larger deficit, which is the #1 thing you need for fat/weight loss.
Plus you get the benefit of EPOC from HIIT which you don't get from steady state, walk/job on the treadmill for hours.
So burning more calories is advantageous when your primary goal is to drop fat. Sure you can ride the elliptical for two hours a day and burn calories or you can spend 30 minutes doing some kind of fast paced interval training and burn a similar number.
Keep in mind that regardless of the type of exercise you're doing, it's just for a short period, say 30-60 minutes or so. The other 23 hours in your day are much more important for burning fat and you need to consider sticking to some of the basics of good health and fitness.
Your lifestyle will greatly affect your ability to burn calories, boost your metabolism, and shed fat, so don't rely on cardio (or any other type of exercise) for weight loss.
The Bottom Line
The most important thing when trying to lose weight (or fat really) is being in a calorie deficit. Without one, you cannot lose weight. Period.
You can burn 700 calories through exercise in be in a deficit, but if you turn around and eat 800 calories later in the day, your deficit is now gone and you won't lose weight.
Another critical thing to understand is that your diet is going to play a far greater role in your fat loss efforts than exercise and is responsible for around 80% of the results you see in your body composition.
Worrying about the "fat burning zone" is not only flawed but a waste of your time. Instead, focus your energy on eating a super high quality diet rich in healthy fats, lean proteins, and veggies.
And as a side note and this is something I feel strongly about, you need to enjoy your exercise because when it becomes a chore, things start to fall apart; meaning, you'll lose focus/interest/motivation if you hate doing it.
If you love walking on a treadmill at 3.5 for an hour because you get to watch Judge Judy, then do it. If you can't stand being inside a gym, don't go to one.
There is always a way to find exercise in doing things you enjoy. Except playing video games..really hard to get fit playing WoW.
For me personally, I prefer to be outdoors hiking, walking, running hill sprints, and using calisthenics for many of my workouts. The gym is OK but it's a bit boring and I like to get sunshine and fresh air.
You might love the feeling of being in a gym, hearing a bunch of dudes grunting and if that drives you, then I'm all for it. Just make sure you find something that will keep you motivated and consistent.
Low Intensity Isn't Bad
I want you to understand that I don't hate low intensity exercise at all.
Because while it's not nearly as effective for weight/fat loss, it is great for overall health, feeling better, improving mental clarity, as well as adding to the overall number of calories you burn.
Walking is one of my favorite activities and I try to get in 3+ miles every day. Plus, there are some tremendous benefits to walking which have nothing to do with fat burning.
But when you do want to burn fat, your best bet is sticking with high intensity training mixed with strength training and a solid diet.
Forget the fat burning zone and get out there and crush it..