Charge 3 Calorie Accuracy Tweaks and Tips

[ErikBak]

Hi There! I've just bought my Charge 3 and i have some questions regarding the Calories Burned records.

I'm 28 years old, 1,86m tall and weight 98kg with 17% body fat.  My daily routine consists of waking up at 6h30 am, taking the subway to work and staying there until 17h40, where i leave for the gym and have a workout of around 1h10 ~ 1h30. This workout is composed of weight lifting with active rests of 4 series, spread through the entire workout, composed of 4 sprints of 1 minute with 1 minute rest in between, where my heart rate should be around 163 ~ 176 bpm. Then i just head back home and try to sleep at around 11pm.

The reason i'm giving all this info is because after i bought the charge 3, i've started using it the entire day to keep track of daily calories burned as well as my heart rate throughout those sprints. The heart rate seems fine but it's saying i'm burning up to 4000 to 4500 calories a day. I've speaked with my nutricionist, which i've been consulting with for a while, and she says these numbers are way off.

Is there any way i can make these numbers more realistic? Any tweaks, configurations and stuff like that? Thanks!

[SteveH]

Welcome to fitbit!

I'm not sure that the numbers are that far out.

4000+ calories is a lot but you are a big guy and quite active and the numbers may be ok.

Are you taking into account your BMR calories? These are the calories you burn just keeping your body alive (even when asleep) and they can be more than the calories burned through activity for many people. There are online BMR calculators that can be used to help check fitbit's numbers but these will not include the calories burned through activity.

Did your nutritionist have any thoughts on what the numbers should be?

What about your step count? What sort of daily total are you getting?

If your calories are being calculated incorrectly then there's not really a lot you can do. You could tweak your profile settings for age, height, weight etc but it's a bit trial and error. It is though worth checking they are set correctly in your profile though - if one of them is wrong then your calories will be wrong.

[ErikBak]

Hello there Steve! Thanks for the reply!

So i calculated my BMR online and the method that most gave me calories to burn was the Katch-McArdle (where i also input my body fat) and it gave me a 3297 calories according to what i think my exercise routine is (Intense exercise: 45-120 minutes of elevated heart rate activity.). Even if we include the calories of my exercise i don't believe i will reach 4000, let alone 4500.

The numbers my nutricionist gave me are somewhere in the 2800 calories.

The daily total of steps i'm getting is between 16.200 and 16.850.

My age, height, weight, fat % and wrist i'm using the charge 3 are all correct. Maybe the automatic step lenght is wrong, but i have no idea how to measure that hahaha.

Thanks again Steve!

[SteveH]

The step length won't be the issue as that only affects distance calculations. 

I believe fitbit uses the mifflin st jeor method of BMR calculation. 

I'm not sure what else to suggest. Perhaps see how it goes over the next few days to get a better feel for the stats and see what other thoughts people post here. I still feel that the numbers sound ok but clearly you are in a better position than me to judge that.

[Parkersspace]

Honestly at your age and activity level i think your charge is more accurate.  If you really wanted to be certain you could see if you could borrow at garmin from anyone with a chest strap for HR and see the difference.  I burn 3500 to 4200 in the winter when i teach skiing 7 hours a day, 7 days a week.  I know I lose weight very quickly in the winter when i do this and I get starving and up my food.  In the off season when i bike i burn only 2200 to 2500 and I am 54 and female. On a day when i have a net flix burn, i burn what they say someone my age burns, only around 1400 to 1600 on a lazy day.

Check what you burn on a lazy day, i bet at your age, with the amount of muscle you have it will be close to that 2800 your nutritionist thinks.  She is not allowing enough calories for the intensity you work out at and your percent fat/muscle.  Nutritionist are not Sports specialists, they don't necessarily understand the intricacies of HIT and muscle building.  I know mine is fairly accurate (though it's a fitbit alta) on the calorie and HR recording as I track everything that goes in my mouth since long before there was internet to track it with and everything I expend.  My fitbit confirmed for me that bike rides and skates do not burn nearly as many calories as the on line algorithms would give credit for which I knew as i wasn't working as hard as I would need to burn the estimated calories.  FItbit confirmed for me that a trail ride burned 50% more for me than a road ride even though the speed is much slower, and i knew this already as i didn't sweat on road rides.  Skates were the same, on line estimates said 700 plus an hour but when i used my measured Heart Rate tracker it showed i burn only around 400 an hour for skating, which again, i knew i wasn't tired or breaking a sweat.  

All this and the only issue now is believe the calories reported on food items when trying to stay balanced!.  I do okay, if i keep myself at a 500 calorie deficit (this allows or things I take a little extra of or don't count) I maintain my weight, when i eat more i go up and less I go down.  Science is amazing when the tools work.

[Parkersspace]

Oh for tips, I do not link to Strava or Mapmyfitness or any other apps that report their own calorie totals, as I found that fitbit did not want to send information due to proprietor algorithms and information to the apps so instead they take the calories the apps report and put them down as burned calories based on the apps algorithm not your heart rate.  These apps algorithms for burned calories are based solely on averages and not nearly as accurate as your heart rate information for what calories you are burning.  The exercise really does not change the calories burned it just increases your heart rate and how you are working, so the most accurate way to monitor calories is with a good Heart rate tracker.  I leave nothing linked to my fitbit accept myfitnesspal for the food inputs to be carried over the fitbit dashboard and my exercise calories are reported back to myfitnesspal so it tells me what I should eat in a day to stay balanced.

Now one other point is the Fitbit does smooth the HR measure over 1 minute intervals so if you hit your peak Heart rate for under 1 minute it will round the average of that minute and report it as the HR for that time.  So you might hit 183 and see it on your fitbit, but you held that HR for only 5 seconds so then later you look over your workout and you don't see it was at 183 but you know you showed that this would be the reason.  For that entire minute you may have only averaged 175 when it's all rounded in the fitbit algorithms, so it doesn't show the seconds you spent at the higher level.

[Parkersspace]

One more point, the longer you wear the fitbit the more accurate it will become on the calorie reporting, resting HR and fit numbers.  It does need good data to track it more accurately.  

My favorite app for daily needs i have used from the year 2000 is here at Nutriondata.com.  It says at your height and weight, you would burn 2883 if sedentary (a netflix binge day doing nothing) and does say your BMI is high.  at 17% fat though you don't need to lose too much and a young male with more muscle content than average can have a higher than healthy BMI while still being healthy.  You could lower your fat by 2% though to gain some health benefits.

https://nutritiondata.self.com/tools/calories-burned

[Parkersspace]

One more tool you may find useful that will break down your Heart Rate tracked to seconds that someone designed and i got from him on one of these forms is at this link.  Can't recall my initial sign in to it but it will take a time i enter and show the seconds. (https://iccir919.github.io/pulseWatch/public/dashboard.html#access_token=eyJhbGciOiJIUzI1NiJ9.eyJhdW...)

App Authorization

[ErikBak]

Thank you for all your input! I will take them into consideration and check the tools you've suggested!

Its very good to know that the more i use it, the more accurate it becomes. If i knew that beforehand i would have waited a little bit more before posting this as i started using it on this monday, so its my third day with it hahahahaha.

[JasonLNoel]

I got you 🙂

Change your max heart rate and it will be much more accurate.

I am 37 and very fit... BUT Fitbit puts  my max HR @183 when in reality it is 200. As soon as I changed this it made a Mega difference in calories burned :fire:🤘😎 and is almost exactly the same as my Garmin now .

[Parkersspace]

I've often wondered if i should change that on my Jason, but i'm not sure how to work out an accurate and real max heart rate,so i continue to let it say the average for my age.  I know when i work out my Heart Rate goes higher than the max it says, based on my age of 55 subtracted from 220, or what ever the formula is.  My calorie burn it reports does seem to be relatively close to accurate though.

[charliegirl57]

Fitbit Charge 3 is horrible when it comes to calorie count.  I walk the same route, twice a day, 6 days a week.  EVERY time the calories fluctuate by 500-1500 calories.  It's a JOKE!!!

[Parkersspace]

Interesting.  Do you have your weight and all stats in correctly?  Have you made sure that no apps are linked to the fitbit account so it only uses your heart rate to determine how many calories you are using?  These are the two things I had to do to be sure I got accurate calorie counts.  When strava and mapmyride were linked to my fitbit account i would use their app counts instead of my heart rate.  Also if you manually enter the exercise it uses an algorithm that is very inaccurate instead of your heart rate.  As I said I track everything for years now and i find the Heart Rate tracking quite accurate and the algoritym to determine my calorie burn by my weight and Heart rate seem very accurate.  My exercise calorie burn and daily calorie burn does not fluctuation much unless i did more and then it shows that my heart rate was higher for longer.

[charliegirl57]

Thank you so much for taking the time to reply. I have no other apps linked to this. My weight, height is logged accurately but since day 1, the calories are completely off on a daily basis. Unfortunately, I purchased this just over a month ago so I am unable to return. I thought it would calibrate itself over time. No such luck. I guess I have a lemon!

[Parkersspace]

I had an inspire that did not track anything properly, i was able to wear my Alta HR and another chest hr that showed it.  I was in time to return mine and bought the charge.  Maybe it's actually not working right, you have a 1 year warranty.  Try getting hold of fitbit support and see what they say.  If you can show the walks being so far apart on the same distance they may send you a new one.  What is happening to you is not typical.  I've had great success with Fitbit support when my items are under warranty.  Contact them and be prepared to email them screen shots of the erratic recordings.  Sounds broken to me.

[charliegirl57]

Thank you so much!!