Fat Burn Zone?

[ChrisBair]

I am curious where Fitbit gets the evidence that a moderate heart rate burns more calories from fat. My colleague and I were having a discussion about this and I could not back up this claim.  Thanks for the help in advance,    (from fitbit)FAT BURN ZONE

Fat burn zone, which means your heart rate is 50 to 69% of maximum, is the low-to-medium intensity exercise zone and may be a good place to start for those new to exercise. It’s called the fat burn zone because a higher percentage of calories are burned from fat, but the total calorie burn rate is lower.

(from webmd)4. TRUE OR FALSE: Moderate exercise promotes weight loss more effectively than vigorous exercise.

FALSE.  Weight loss is a matter of simple arithmetic: To shed pounds, you must burn more calories than you consume. And when it comes to burning calories, the greater the exertion, the greater the rate at which calories are burned.

Working out at about 60% to 75% of your maximum heart rate (the so-called "fat-burning zone") burns fewer calories than working out at 75% to 85% of your maximum heart rate (the so-called "aerobic" or "cardio" zone).  

But caloric burn depends on a workout's duration as well as its intensity -- and it's easier to work out longer when exercising at a lower intensity.

http://www.webmd.com/fitness-exercise/features/the-truth-about-heart-rate-and-exercise?page=3

Edit:

I did find this to possibly help explain but it looks rather deceiving to build a product around it..

http://www.builtlean.com/2013/04/01/fat-burning-zone-myth/

30 Minutes of Exercise	Fat Calories Burned	Glycogen Calories Burned	Total Calories Burned
Low Intensity Group (50%)	120	80	200
High Intensity Group (75%)	140	260	400

Moderator edit: updated subject for clarity

[Michael]

You will notice the WebMD FAQ was answering something different than Fitbit's claim.

Fitbit claimed: "the fat burn zone because a higher percentage of calories are burned from fat, but the total calorie burn rate is lower." Which lines up with what WebMD says.

Here is a link that I think explains it well. With a chart even:

[ChrisBair]

I just edited the post with that same logic. It seems like a deceptive practice. You burn more fat at a higher intensity in the same period of time. Seriously think they need to ammend their verbage on that if this is the logic behind it. You can't build a fitness regiment around something like that, which is the point of their product. 

[MikeF]

Doesn't the chart back up the claim? Where is the deception?

[Knowledge]

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@ChrisBair wrote:

I just edited the post with that same logic. It seems like a deceptive practice. You burn more fat at a higher intensity in the same period of time. Seriously think they need to ammend their verbage on that if this is the logic behind it. You can't build a fitness regiment around something like that, which is the point of their product. 

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I totally agree, but I don't think this is deceptive marketing by Fitbit. The reality is the fitness community has been mislead in general for many decades by this "Fat Burn Zone". It essentially makes no sense and almost all fitness experts will tell you that working at Cardio or close to Peak HR will be best for overall health and calorie burn. Calorie for Calorie you burn MORE fat per minute in a Cardio/Peak zone than in Fat Burn Zone, but because of the ratio, "Fat Burn Zone" burns more fat than lean muscle.

[Knowledge]

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@MikeF wrote:

Doesn't the chart back up the claim? Where is the deception?

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The deception is that in a workout, OVERALL Fat burned will be more in a high intensity workout than a moderate intensity workout.

It's silly to calculate things as a ratio of Fat to lean muscle because if you are strength training and doing cardio to lose weight, you will preserve that lean tissue through the strength training but will increase your overall fat metabolism in the cardio workout vs a moderate intensity workout.

[sdbelle10]

Ehhhh that could be a bit of the grey area. Your body prefers to use muscle as energy rather than fat, so if you're focusing purely on cardio/trying to retain muscle mass, working out in a fat burn zone for longer will mean that you're keeping as much muscle mass as possible. Especially if you're eating in a deficit and doing strength training, you wanna make sure you're loading up on protein and if you do cardio, do moderate cardio in the fat burn zone to save as much of your muscle as possible.

[sdbelle10]

I think the thing to look at isn't fat calories burned but the glycogen calories burned. Its counterproductive to focus on bulking up if you're going to turn around and eat up the muscles you just built up from cardio. This is why its very rare that someone is amazing at cardio and lifting. They require and use different things.

[ChrisBair]

 Deception would be that you are burning more fat at a moderate heart rate than a higher heart rate. There is no such thing as a fat-burning zone. You are burning fat at all levels and that increases as you go up in heart rate. Its probably just a marketing thing on their product. Anyways, I think Fitbit is probably careful enough in their language after looking at it again. If you are looking to get below 10% body fat it is going to take a lot of intense workouts...

[Michael]

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@ChrisBair wrote:

Deception would be that you are burning more fat at a moderate heart rate than a higher heart rate. 

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@ChrisBair Yes, that would be deception if they said that. But they didn't. They said that a "higher percentage of calories are burned from fat" which is true. I'm sure some people will misinterpret it, but there is nothing they can do about that.

[miig]

Aiyyeee ... I was mildly confused by what FitBit was telling me about the Fat Burn Zone, so I found this thread and now I'm MORE confused. 

I'm trying to lose weight (65+ pounds) and my current plan with the Fitbit is a deficit of 750 calories. So far (since December) I've been doing 30 minutes on the elliptical (HR = 160 - 170 which Fitbit calls "peak zone") and then doing circuit training for about 20 minutes - legs & arms & abs. As I'm losing the weight, I'm hoping to tone (especially my arms). About a year ago I was working with a personal trainer and this is the kind of regimen he had me doing, gradually increasing the weight on the machines. He told me I was building muscle to help burn fat and that the cardio is also important to burn calories. 

As far as fat burning goes, is this completely wrong? Should I not be doing cardio AND circuit training? I find it really difficult to stay within my "fat burn zone" (unless the Fitbit is overestimating my HR) - to do that I would have to go slow and focus on going slow the whole time. If I just go at my natural pace where I don't feel like I'm racing someone and I feel like I'm working up a sweat but it's not strenuous and I can keep the pace for 30+ minutes, my HR is always at 168 or around there. 

Even if I ignore the Fitbit and use the elliptical on the "weight loss" workout (inputting my age and weight and target HR) it CONSTANTLY tells me to slow down and I just ignore it. 

But it sounded like you were saying that I'm building muscle with the strength training and then burning it all off with the cardio on the elliptical (since my HR is about 20 BPM higher than my "fat burn zone.")

Ugh! Help! 🙂

[Knowledge]

Continue doing what you're doing. You will build far more muscle each day than you would lose while doing cardio. In the long run working out at a high HR like you are currently doing will burn far more fat than a lower HR. Forget about the calories burned from "lean muscle" they will have minimal impact on your strength training. Follow what your trainer says and you'll do great. unless you're competing in a weight lifting competition a high HR during cardio will not have any impact on you!

[miig]

Okay, thank you! 🙂 🙂

[sdbelle10]

Yeah you should be fine. If you're focusing on losing weight, you're going to be losing muscle no matter what--by strength training you're just refucing the amount of muscle mass you lose. Also note that strength training in and of itself IS in the fat burn zone. So as you're building muscle you're also burning a higher percentage of fat-giving you the toned look you want.

[sheppardtribe]

well I just don't understand it at all - according to my fitbit I spent over 8 hours in the fat burn range today and over 7 hours in the fat burn range yesterday - I mean if that is the case shouldn't I be a stick insect? I'm 93kg! My heart rate goes as low as 52 when I'm sleeping but if I'm active it goes into fat burn mode - is this the same for everyone? 

[crazylefty]

At higher intensities when you begin to get anaerobic you can't burn fat fast enough so it goes to lean mass for fuel.  If you maintain a lower heart rate your body can use fat for fuel instead for a longer period of time.  I don't think they are misleading at all.

[Tealhanley007]

Hey miig, I would love to become friends on Fitbit!! I'm trying to lose roughly the same amount of weight!! My email I used on here was tealhanley007@gmail.com 😊 Feel free to add me!!

[tobingj]

Just new to Fitbit - 2-3 weeks but noticing the same. Sorry inadvance if i do not phrase things correcly below.

It depends on what your doing. I just spent 3 days office bound and as expected it recorded I was pretty inactive. I took a day off last week and I hit peak doing exercise I hadnt thought would be up there. I was out of breath hiking but never really thought of the exercise effect.

One of the first days I got the band I spent 3 hours out gardening... lifting compost- gravel - weeding- cutting grass and I knew I was tired at the end of it. Synched the hrm and saw I had spent almost 2 hours in high cardio.

It is linking my body feelings to numbers i can translate back into effort. That is great for pushing me a little bit or pulling me back.

The FAT BURN range- as i understand is just a state of activity that increases your metabolism. In effect it allows extra 20%-30% calorie intake without increasing weight. (Total 130% of normal). So if you stay at your normal calorie intake you are in effect in deficit and should loose weight over time. A 20 minute fast walk should get you into this fat burn zone easy enough and then maybe cardio. The cardio would be the 30% - 40% zone and peak is into Professional athlete territory.

So it is easy to do exercise to allow for a nice fat burn. Tougher to get the 40%+. Just add in walking up the stairs in the office... go to lunch solo and do a brisk walk instead of a slow chatty walk with friends. If you need to print something use the printer 3 floors down. 🙂

[M_Rockstar]

I spend my whole day in the Fat Burn Xone and when I exercise I move to cardio or peak. I don't u derby and how I can have this zone and my normal or steady and still have any fat on my body. It seems too complicated and Fitbit won't address this and I just don't understand it. My resting pulse does change do I know the fat burn zone would vary with it , but...?

[tobingj]

Fatburn zone is not that clear cut. It is an estimated BPM. At 95 your not
fat burn and 96 your cardio. Use it as a guide. Push as hard as you can for
as long as you can. 🙂