Charge 2 calories burned too high

[LisannevdL]

I just got my new Charge 2 on saturday so I've not tested it very long, but the calorie count on it seems WAY off. The BMR on it seems correct for my height/weight (1555) but then the calories burned when simply walking a bit are way too high.

Saturday, I went shopping for a few hours that got me around 10k steps in total. I also did a kickboxing workout (268 cals) and went biking (219 cals) and Fitbit calculated 3000 (!!!) calories burned that day. That just can't be right, when my BMR is only 1555 I should've burned 1445 cals with exercise according to Fitbit. Subtract the kickboxing and biking (which is way higher intensity than the walking, calories for that seem correct) from that and that leaves 958 calories burned for walking +/- 10.000 steps.

Has anyone else had this problem? I've Googled for a bit and it seems it was a problem back when the first Charge HR was released too, but I couldn't find a solution. I love the Fitbit and the app but it seems when it takes the constant HR into account when you're not very fit it just overestimates by a WAY too high number. If I ate what Fitbit is telling me I can eat, I'd gain an incredible amount of weight in a very short time.

The numbers I got when I was just counting steps without heart rate (using my phone, before I got my Fitibit) was way closer to the actual number I should be getting for something as easy-going as walking while shopping.

Moderator edit: format

[ForecasterJason]

In looking at the graph, the highest it reported my HR was 62% of my max. I think it's worth noting that I had the same issue with the calories burned during exercise being overestimated when I had the Fitbit One. So, it appears as though there's something off with the whole algorithm. 

[Stlgal]

I just switched from a Fitbit one to a charge 2 and am getting about 1000 more calories scored on the charge 2 than I got on the one with all other metrics the same (steps on the two devices by contrast are nearly identical).  It is too high

[mollymia]

does fitbit one tracks HR? if it doesn't, then that might explain why. 

[ReallyAwesome]

You DON'T have to be at a surplus to gain weight. With a tdee=caloric intake you can slowly decrease fat mass and increase lean mass, which has much less calories "stored" than fat. Likewise, you can gain weight with a (small) caloric deficit. 

Sure seems this algorithm is not perfect, and studies have already shown that this kind of trackers cannot account for exercise/activity energy expenditure accurately. If I remember correctly, Apple watch was closest but still quite off, some fitbit with HR monetoring was a close 2nd. No studies on TDEE accuracy yet, that I know of.

I for one seem to lose weight as planned with my charge 2 and HR turned on, meticulously registering all calories. Well, almost as much as expected anyway, but I certainly gained some muscle mass too (as a beginner at weight lifting this is quite easy). I agree though that the walking calories seem too high. 

Perhaps the algorithm works well for some average person but not for all? This thread is obviously going to attract those who Google "fitbit calories too high", that's how I found it, worried that my walking calories were totally off. But the weight loss came and now I'm not so worried any more 🙂 

[mollymia]

well, my charge 2 tells me i'm on a caloric deficit ranging from 300s to as high as 700s everyday (except for my weekly cheatday, whereby i'm either "in zone" or have a surplus). 

been months and my weight has been constant.

either i'm miraculously still losing fat and gaining muscle, or charge 2 really over-estimates our calorie expenditure. 

[N6IO]

I have also noticed that since going from a flex to a charge 2 with heart rate - my reported calorie burn has increased by about 300 per day.   I have more than 3 years of data logged, so it's easy to see trends.   In my case I'm pretty sure it's because while my resting heart rate is in the mid 50's, just casual activity like slow walking to get coffee - not to mention drinking the coffee - brings my heart rate to the 90 range.  The fitbit estimates this increase in heart rate as the result of increased activity.  It often shows I'm in the "fat burn" zone when I'm just standing or doing very light activity.

Based on a tip from early in this thread I increased my maximum heart rate to 200 - and it has made the number of minutes it says I'm in the fat burn zone much more accurate.  It's only been a few days, but from what I can tell the calorie count is much more accurate now.

Any health experts know what it means if moderate activity almost doubles your heart rate?  

[Ka14mrn]

Hi there the calories are stated in kilojoules so you would share it by approx 4 to get the correct calories 

[stuman74]

I switched over from Apple Watch to Charge 2 around Thanksgiving.  After almost 2 months of usage, while I love the battery life and sleep tracker/alarm, I think that FitBit credits me with way too many calories burned throughout the day.  I know you can burn calories laying around all day, but since I have this linked to MyFitnessPal which makes adjustments from activity, I was wondering if there is a way to ONLY reflect actual workouts from the FitBit for my calorie burn?  I'd rather err on the side of burning more calories than I get credit for.  I know an option would be to abandon FitBit and just use a chest HRM and tracker for recording workouts, but I'd like to use this Charge 2 if possible.  Basically, eliminate any credit for steps...that would be fine with me.  Thanks!

[mjcarp0221]

In my case, using the Tennis activity, I'm seeing a calorie burn number almost double that of manual calculators. For example, at 182 lbs playing doubles tennis would burn an average of 300 calories per hour. This number varies somewhat when I used different calculators I found online. However, based on my last 2 outings, the Charge 2 calculated 532 and 556 calories per hour! If this has something to do with calculating steps in addition to the calories estimated on heart measurements, then how to you get down to the correct calculation???? I think my next game I will select "Run" as my activity and see what happens. In my situation I am trying to lose weight and using calories burned from the Charge 2, I'll never lose using the calculation of calories burned and calories in. In fact, I'll probably gain weight.

[oll_Gi]

@mjcarp0221i think regardless of the activity you do, the calories burnt are calculated ONLY via Heart rate measurements.

If it was possible to stay relaxed on bed and get 160bpm

or running at 160 bpm,

it doesn't matter you will burn the same calories as far as the tracker is concerned.

So check your heart rate measurements on your recorded tennis workout and see if they look normal and responding to your activity.

[mjcarp0221]

Thanks for the reply and did some calculations as a result of your input.
Amazingly, if I use online calculators, it turns out the Fitbit is actually
lower!!!!!
Here is my example:
Fitbit calculated 1260 cal for a 136 minute workout

Online calculators at my average BPM came up with 1700+ calories burned
(gross calories)
Subtracting my resting rate of calories burned for 136 minutes of 163
calories yields a net calorie burn for the tennis activity o f 1500+

So which one is correct is anybody's guess.

[oll_Gi]

@mjcarp0221

What I was implying is... fitbit counts calories correctly via bmr. BUT 

If your bmr is measured wrong which happens quite often then the burnt calories will be also wrong. But they will be what you would have burnt if your hr was actually as measured.

I have walks with average HR 135.... that's completely wrong. My resting HR is 56 atm. My walking HR is 90-100. When it's recorded properly. But most of the time it isn't... sadly. 

Or it's fine for 10 mins then spikes and records 160bpm for 10 mins... if I want the calories to be correct I delete the exercise and manually add it along with the proper calories (by my estimations on how hard I worked.). But you lose active minutes this way.

[N6IO]

I switched to an HR device in December and was seeing about 300 cal/day higher reported calorie burn.  I increased my maximum heart rate to 200 a few months ago and I think the reported calories per day is now accurate.  I think the app would overreact to increases in heart rate thinking I was working hard when I was doing a leisurely walk.  So for me I’m happy with it now. 

[jchardin]

I'm almost 76 years old.   I'd love to be burning as many calories as FITBIT says I am.   I wouldn't be packing about 15 extra pounds.   Usually my daily calorie counts are around 3000.   Here are some of the last few numbers,   2764 so far today then 2766, 2420, 3261, 2365, 3294, 3593.   I can't run or bike any more - and I don't swim.   What's burning all of the calories?    (I do some short hikes on weekends) What I'm going to do is to change my age to 86 - maybe that will get my calorie rate to a reasonable number.   It may be that FITBIT is not really setup for working with old farts.  

[bhillc]

My calories burned were higher than I thought but today.....I have 6900 steps at 3 pm and 6600 calories burned??????

[AlvaroFitbit]

@bhillc It's great to see that you've visited the Fitbit Community! Sorry to hear that your calories burned shown are too high. Check your personal information (age, height, weight, etc.) is correct. Also see if you haven't logged any activities for the day affected. It could be that sometimes the activity is for one hour but a simple additional zero makes it a 10 hours one.

Let me know how it goes!

[bhillc]

Hello
It went up to 7200 then somehow reset to a normal 1800. Not sure what happened. All good now
Thank you

Brenda

[N6IO]

What I have discovered is that the FitBit software algorithm misinterprets
the increase in heart rate from moderate activity and thinks that I am
doing strenuous activity. So it records something simple like walking at a
much higher calorie burn rate than it should. I suspect my numbers are
more inaccurate because my resting heart rate is relatively low at 53 and
my moderate activity heart rate is closer to 80. It seems the software
sees this jump as a big change in calorie burn rate, but it is not.

I have corrected this by manually setting my maximum heart rate to 200
instead of whatever the default would be for someone 63 years old. This
has brought my calorie burn rate down to a more realistic level. Over the
last 6 months or so it logs my calorie burn at about 300 per day higher
than I eat, and my weight is not going down - so it's still wrong, but
before it was more like 600 too high per day so this is better. I don't
want to raise my maximum heart rate above 200 because it starts making
reading some of the graphs difficult.

It would be nice if FitBit had some sort of correction for this, but the
manual setting works.

[Jiorgos]

 I am ditching fitbit. Sorry. There is but one function that I wanted it to have and that was calorie tracking. 

I used a Samsung tizen prior to this and it was very very accurate. This charge 2 gave me 2400 cal by simply walking half an hour.

I want to stress that my profile data is correct and precise.

Just sad about the money I ve spend .. I just wanted something smaller on my wrist but i will get my Samsung back.  Total disappointment... 

[Jiorgos]

I can attest that fitbit calculation for calories burned is absolutely off and stupid. 

If they issue no fix for this I will be ditching the watch quite soon. Worst money I have spent in a long time.