Fitbit overestimate of calories used that feeds through to MFP

[Portsian]

Hi there

Anyone else noticing that there is big overestimate of exercise calories that the Charge 2 is making? This feeds in to myfitnesspal app, so shows 'extra' calories I could eat. If I followed this I would be gaining weigtt. I have just updated from Fitbit to Charge 2, and the old Fitbit was much more conservative in its calorie estimate. If is is really overestimating then I don't want to use it

Moderator edit: Clarified subject

[BrezSC]

I did something very simliar, i am 5 ft 10, but tell fitbit that i am 4ft 2. took me several months of adjusting my height to "calibrate" the calorie burn equation with the charge 2.

you would think that this would be an easy fix for Fitbit, a simple calorie offset in your profile, that lets experienced users adjust from generic formulas to their specific body

[MyZenNolan]

I've noticed you can now set the fitbit food plan based on "sedentary" rather than personalized. This may fix the issue (Though I do notice a 100 calorie bonus above every other tdee calculator out there).

I will update in a week and tell you all how it goes 😉

[BrezSC]

Hey thank, I would be interested to hear.  I found that Fitbit overestimates for me about 250 calories per day, after more than 4 months of trial and error study carefully tracking my actual weight and caloric intake daily.  The weight and caloric intake data I could solve the equation for how many calories I actually burned versus the fitbit number.

[pehts79]

I just changed my age from 38 to 18 and my height from 5'7 to 4 feet tall in the hopes that it reduces the overestimate...

[Strivingforit]

Feature board? Asking for the device to work as advertised is hardly a feature request. It's consumer rights.

[Kyrielle]

Regarding the dominant wrist thing.  I read about that and made sure my fitbit was set to sit on my dominant wrist.  It does, in fact, cut your steps and calories calculated in half.

So, for those people claiming they're burning like 300+ calories for a 15 minute walk, I can confirm that switching the setting so that both wrist settings are the same (sitting on your dominant wrist) corrects the issue.  I get only 90 calories burned on a 15 minute walk, which matches with all of the other burn readings I've gotten from various apps and calculators.

[mu71rd]

hi, just interested in how you have found your estimates since you changed that data. It's a clever way to try and force fitbit's algorithms to show you something more useful.

I've been -750 pretty accurately for the last few weeks and not lots any weight. The problem is worse the more exercise I do - great device hey!

[BrezSC]

I think the data is accurate now that I am 4ft 2 inches.  I lost 27 pounds.   But the sad reality is it took me 408 days.  I wanted to believe I was burning a lot of calories, but the truth is I am 5ft 10 and weight 170 lbs.  I burn only 1900 calories on days I do no exercise.

[RobertoME]

Hi there @BrezSC and @mu71rd. thank you for visiting the Fitbit Community! I was reading your posts and I just wanted to share the calorie burn estimate that Fitbit provide,s takes into account your BMR, the activity recorded by your tracker, and any activities you log manually. 

By changing the data that your Dashboard use to calculate BMR, it might throw incorrect numbers. Your basal metabolic rate is the rate at which you burn calories at rest just to maintain vital body functions. This usually accounts for at least half of the calories you burn in a day and is estimated based on the physical data you entered when you set up your account: gender, age, height, and weight.

To give you an example, I am about 5.7 ft and I weight 200 lb. The result of my calorie rate just for BMR is 1,800 calories, not counting exercises.

Hope these details helps. Stick around if you have more concerns.

[BrezSC]

Thanks,  I appreciate your contribution to the discussion.  My point is not that I dont understand what the fitbit is doing, it is that Calculations of BMR are estimates for a population in general, not for a specific individual.  I meticulously logged every bite I ate for 408 continuous days; additionally I logged calories burned with my fitbit.  I can easily calculate how many calories I burned over very long periods on the scale.  3500 calories equals a pound.   This is worthless information over a couple of weeks, but over hundreds of days I can pretty accurate tell how many calories I burn from the calorie log and the scale. 
For me, specifically for me, the fitbit overestimates how many calories my body burns.  The whole point of my post was that fitbit does not allow users who have command of the mathematics of weightloss to enter a factor for their bodies to accurate reflect real results.  Therefore I was posting a suggestion to users how to "hack" the calculation to make it more accurate.

[mu71rd]

yes. this!

BrezSC exactly hits the nail on the head here. It would be so easy for fitbit to implement a calibration or adjustment to the overall maths of the 'softw'are, but that would require acknowledging that this is a needed change. 

All I've seen so far in the 10s if not 100s of articles about this exact subject is copy and paste answers from fitbit representatives, which completely avoid the actual question, and imply that the question is wrong, and that the answer is actually the answer to a different question. 

Fitbit - this is a real situation, which could so easily be fixed by acknowledging that some people do not find that your calorie in vs calorie out maths is correct. My case is exactly this. Over a long period of time this is easy to witness.

Please keep this thread going if you want fitbit to act on it, and fitbit, please don't just provide us with the link where we can suggest features and upgrades - as that is the graveyard for all discussion of this nature. 

[Rich_Laue]

3500 calories is not equal to a pound of fat.

The body has to types of fat subcutaneous fat and visceral. they have different compositions with a different caloric energy in grams 

The 3500 can be traced back to 70 years ago. 

[-kx-]

Sorry Rich but this is another example of a useless reply.

First and foremost, you are de-railing the conversation and not adding to it. The issue here is that the Charge 2 has been found by a very very large number of users to over-estimate activity calories by between 10 - 40%. If the formula cannot be fixed, we want the option to manually offset.

Secondly, if you wish to cite sources for such claims, please cite actual reputable journals or scientific sources. The blog you linked to is neither, and greatly abuses takes liberties with the actual facts of those articles it references. To call this pseudo-scientific malarkey is more honor than it deserves. And arguing something is incorrect due to being 70 years old is no more useful - I suppose we may as well through out Newtonian physics and the Pythagorian maths as well? I am not saying I agree or disagree, but please don't make such misleading posts.

There is no disagreement about BMR calculations - people are abusing the values they can adjust (those impacting BMR as well as mis-selecting which write the device is on) to jerry-rig the formulas in an attempt to get somewhat useful values.

The real issue needs to be fixed, and anything not working in that direction or misdirecting users with irrelevancies needs to stop.

[BrezSC]

it is empirically close enough based on my experimentation, but if that is not the right number
what is?  people need to know what to do, not what not to do

[-kx-]

Regarding what to do, here is some more information for you. I've put it behind a spoiler tag so as not to distract from this conversation for the sake of those who don't care about this.

Spoiler

When your weight changes, whether up or down, it is not simply a change in fat, because the body is not made up entirely of fat. There will also be changes in water, muscle, glycogen stores, etc... The maths that give you the '3500 kCal/#' number only work for triglycerides and don't apply to any of these other changes. So for example, water and glycogen gains could offset the fat burn, which would ruin your math. Failing to account for things like this is - quite unfortunately - what lends weight to the twisted arguments of those who speak against energy balance preservation (i.e. Calories in / Calories out).

If you have a diet with very strict adherence where your carbohydrate and hydration levels tend to remain constant (regardless of whether low or high), and are weighing yourself under consistent circumstances, and are not building muscle or losing it, the 3500 kCal/# number can come out very close to true, but this is very very rarely the case.

In the real world, even if you think you are being extremely strict, you'd best allow for at least 10-15% variation as you will have some lean body mass loss or gain, as well as needing to account for upper limits on how much excess fat your body can burn a day (there is a formula for this which you can find in the last reference).

For those who'd like to read the science themselves and learn more:

- Heymsfield SB et. al. Energy content of weight loss: kinetic features during voluntary caloric restriction.Metabolism. 2012 Jul;61(7):937-43.
- Thomas DM et. al. Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule.Int J Obes (Lond). 2013 Dec;37(12):1611-3.
- Schoeller DA et. al.Effect of dietary adherence on the body weight plateau: a mathematical model incorporating intermittent compliance with energy intake prescription.Am J Clin Nutr. 2014)100(3):787-95.
- Dhurandhar EJ et. al. Predicting adult weight change in the real world: a systematic review and meta-analysis accounting for compensatory changes in energy intake or expenditure. Int J Obes (Lond). 2014 Oct 17.
- Hall KD et. al. Quantification of the effect of energy imbalance on bodyweight. NIH NIDDK (Lond) 2011 Aug 27.
- Speakman & Westerterp. A mathematical model of weight loss under total starvation: evidence against the thrifty-gene hypothesis. Dis Model Mech. 2013 Jan 6.
- Alpert SS. A limit on the energy transfer rate from the human fat store in hypophagia. J Theor Biol. 2005 Mar 7.

[mu71rd]

Thank you. That’s useful information. However I believe a trend of 400+ days is enough data to accurately tell whether Fitbit is simply over-egging its calculations.

Besides which, there is enough fluctuation across the human species for how the body works, and enough examples on this forum of folk saying the calculations for them are wrong, that the right thing to do is put in some kind of alteration procedure in an advanced setting somewhere to allow us to adapt it.

It’s what should happen, as you’d only need adjust it if you had a problem - a bit like the left handedness thing. I don’t understand why Fitbit won’t implement it. I suspect it’s because Fitbit want to be able to blame people’s lack of weight loss on factors beyond their control. It maintains the ‘emporer’s new clothes’ illusion.

[-kx-]

I completely agree with you, mu71rd. I'm sorry if that wasn't clear.

The extra information I provided in response to BrezSC was only to clarify per his request, and to show that while there are options available to determine with a reasonable deal of accuracy, they are extremely involved and mostly outside the limit of what we can or should expect from Fitbit.

I don't think you are alone in tracking over the long term; I know other users (myself included) well into thousands of days, and I think with far less than 400+ days that meaningful correlations can still be drawn (in the interest of fending off any truly pedantic arguments, I am well aware that correlation is not the same as causation, that does not make it un-useful).

I definitely agree that what should be done is to have a simple setting for adjustment for those who find the stock calculations to be inaccurate. It could be well buried and have many warnings and caveats, but it certainly should exist.

Ultimately, Fitbit keeps stressing that these are not medical devices and not to be taken as medical advice, and all the usual disclaimers. Since that is the case, I see no reasonable explanation why they cannot add adjustment offset and/or multipliers for reducing how many calories are registered from activities. It should be the users' choice.

[SunsetRunner]

All I know is that when I had a fitbit flex back in 2013–2014, it took being on my feet ALL day and walking 10,000 steps to burn 2100 cal.  

.

The charge 2 tells me that I can walk 7000 steps and mostly SIT on my butt all day, and burn 2100 cal.

.

 That’s a pretty big discrepancy. 

[Rich_Laue]

@SunsetRunner have you taken a look at this post on MFP calories. 

MyFitnessPal: How to correct calorie discrepancy f... 

[SunsetRunner]

@Rich_Laue

Thank you so much for your reply. 🙂

I had not seen that post because I do not use my fitness pal.

My comment was more directed towards fitbit in general and how the Charge2 shows that I burn more calories than either of my previous two fitbits did. 

Thank you though!