Does your Fitbit overestimate calories burned?
daniip_la
Posts: 678 Member
I bought a Fitbit One a few weeks ago, and I'm really enjoying it. I'm goal-driven so I like to try to beat my numbers everyday since getting it. I've gone from almost no extra walking to 5 miles most days.
My worry is that it's grossly overestimating my calorie burn. I'm 26, F, 6', and 326lbs as of this morning. I've attached a screenshot of my Fitbit info from Wednesday.
I've lost a few pounds since getting the Fitbit, but I don't know if I could be losing more. I don't eat back all the calories MFP adjusts to give me. On Wednesday, for instance, I ate 2200 and MFP/Fitbit said I had 500 left. That's how most days go.
Anyone else experiencing this, or have any advice?
My worry is that it's grossly overestimating my calorie burn. I'm 26, F, 6', and 326lbs as of this morning. I've attached a screenshot of my Fitbit info from Wednesday.
I've lost a few pounds since getting the Fitbit, but I don't know if I could be losing more. I don't eat back all the calories MFP adjusts to give me. On Wednesday, for instance, I ate 2200 and MFP/Fitbit said I had 500 left. That's how most days go.
Anyone else experiencing this, or have any advice?
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Replies
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Fitbit can overestimate for some and underestimate for others (I think my Flex underestimates). It's certainly possible the numbers are a bit off for you.
My advice would be to log your food as accurately as you can for 4-6 weeks and eat back a portion (say, 50%) of the Fitbit calories earned. After 4-6 weeks, evaluate your weight loss and see if you need to eat more, eat less, or if you're losing as expected, stick with the 50%.
ETA: Do you have MFP and Fitbit set for the same amount of weight loss per week?
~Lyssa1 -
Mine overestimates, so I changed my height down an inch to lower the BMR. It's pretty accurate now. But like macgurl said, you might want to first average out some trends over a few weeks and see if you're losing at the expected rate or not.4
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Mine underestimates by a little bit. I could raise my height to compensate, but I'm ok with losing a little faster than expected.
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My One seems to be right on, or underestimating very slightly. Your burn does seem high at first glance, but I'm 5'7" and 140 lbs, and mine gives me about 1,950 Cals for a day when I walk about 10,000 steps. At your height and weight, I wouldn't be surprised if you really do burn that much.
I agree with the above that you just have to track and see what happens. When I got my first Fitbit (a Flex), I thought there was no way I was burning what it said I was. But I ate what it said and tracked, and realized it was actually pretty accurate.
I don't think it affects the numbers, but I don't think you need to track your walks separately (the 2 mi walk in the activity section).
Awesome job on the extra walking!1 -
I thought my Charge HR was overestimating until I actually looked up my BMR and my caloric needs based on my activity levels and realized it was pretty accurate.
I inputed your numbers (assuming you are 5 foot 6) in this formula to find your BMR, which is the calories you would burn at your height, weight and age if you stayed in bed all day and didn't move. http://www.bmi-calculator.net/bmr-calculator/#result
BMR = 2261.1
I then used Harris Benedict Equation to multiply times your activity level to find the calories you would need while being active.
http://www.bmi-calculator.net/bmr-calculator/harris-benedict-equation/
Activity Calories
= 3109 (light activity)
= 3504 (moderate activity)
= 3900 (very active)
So your Fitbit may be off just a hair, but not by a lot judging by those numbers.3 -
My One seems to be right on, or underestimating very slightly. Your burn does seem high at first glance, but I'm 5'7" and 140 lbs, and mine gives me about 1,950 Cals for a day when I walk about 10,000 steps. At your height and weight, I wouldn't be surprised if you really do burn that much.
I agree with the above that you just have to track and see what happens. When I got my first Fitbit (a Flex), I thought there was no way I was burning what it said I was. But I ate what it said and tracked, and realized it was actually pretty accurate.
I don't think it affects the numbers, but I don't think you need to track your walks separately (the 2 mi walk in the activity section).
Awesome job on the extra walking!
I track my walks separately because I do them separately. I walk 2 or 3 miles at a time, twice a day, and use the tracking function instead of logging them.
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Chellellelle wrote: »I thought my Charge HR was overestimating until I actually looked up my BMR and my caloric needs based on my activity levels and realized it was pretty accurate.
I inputed your numbers (assuming you are 5 foot 6) in this formula to find your BMR, which is the calories you would burn at your height, weight and age if you stayed in bed all day and didn't move. http://www.bmi-calculator.net/bmr-calculator/#result
BMR = 2261.1
I then used Harris Benedict Equation to multiply times your activity level to find the calories you would need while being active.
http://www.bmi-calculator.net/bmr-calculator/harris-benedict-equation/
Activity Calories
= 3109 (light activity)
= 3504 (moderate activity)
= 3900 (very active)
So your Fitbit may be off just a hair, but not by a lot judging by those numbers.
Thanks for working the math, I'm actually 6' even so that raises it a bit. I know by calculating my BMR/TDEE the numbers aren't far off from what the Fitbit says, I just don't think I can lose by eating that much. I'm used to eating around 1700 with no exercise, and I can't imagine walking adds that much.0 -
The zip and flex underestimated for me by about an avg 200 calories per day. Blaze and Surge seem to be accurate for me.
Considering your weight and height it might not be that far off at all.2 -
macgurlnet wrote: »Fitbit can overestimate for some and underestimate for others (I think my Flex underestimates). It's certainly possible the numbers are a bit off for you.
My advice would be to log your food as accurately as you can for 4-6 weeks and eat back a portion (say, 50%) of the Fitbit calories earned. After 4-6 weeks, evaluate your weight loss and see if you need to eat more, eat less, or if you're losing as expected, stick with the 50%.
ETA: Do you have MFP and Fitbit set for the same amount of weight loss per week?
~Lyssa
Yes, I'm set for a 2lb/week loss on MFP and a 1,000cal/day deficit on Fitbit.
I weigh all my food to the gram on a food scale, and double check calorie entries with the USDA website entry. I'm confident my logging is as accurate as possible.
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Mine underestimates a bit, but almost entirely because it thinks my BMR is lower than it really is (according to multiple tests at a hospital). For anything step based (running and walking) it seems very accurate to me, based on the BMR formulas. If you know your BMR is higher or lower than the estimates, it will be off.
Now that said, I've seen studies that show the calorie calculation is way off on Fitbits. But I have definitely not found that to be the case.0 -
I found for me it defintely overestimated. It would give me 160 calories for a 15 minute leisurely walk and said it was very active minutes. If I manually logged a 3.0 mph walk on the site it would only give me like 65 calories.
For some its accurate and for some its not. The only weigh to know is to track your real world results vs what it estimate and then compare.0 -
I don't know if mine (Charge HR) is accurate or not but it doesn't seem far off based on what I think I'm eating and my loss rate.0
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I feel mine is pretty accurate. I have the One and I clip it to my bra. I usually eat what it sends over to mfp, at least when I can get them to talk to each other properly...but that is a whole different issue.0
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I found for me it defintely overestimated. It would give me 160 calories for a 15 minute leisurely walk and said it was very active minutes. If I manually logged a 3.0 mph walk on the site it would only give me like 65 calories.
For some its accurate and for some its not. The only weigh to know is to track your real world results vs what it estimate and then compare.
Doesn't Fitbit measures total calories not additional calories? On a 15 min leisurely walk you very well may burn 160 calories if BMR is included.0 -
Need2Exerc1se wrote: »I found for me it defintely overestimated. It would give me 160 calories for a 15 minute leisurely walk and said it was very active minutes. If I manually logged a 3.0 mph walk on the site it would only give me like 65 calories.
For some its accurate and for some its not. The only weigh to know is to track your real world results vs what it estimate and then compare.
Doesn't Fitbit measures total calories not additional calories? On a 15 min leisurely walk you very well may burn 160 calories if BMR is included.
Fitbit burns include BMR.
I find my old Ultra and new One accurate. The Zip is very inaccurate for me and I'm sure I got a dodgy Zip.0 -
My charge overestimated calorie burns and steps. But I never calibrated the walking or running strides like i have my garmin.0
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macgurlnet wrote: »Fitbit can overestimate for some and underestimate for others (I think my Flex underestimates). It's certainly possible the numbers are a bit off for you.
My advice would be to log your food as accurately as you can for 4-6 weeks and eat back a portion (say, 50%) of the Fitbit calories earned. After 4-6 weeks, evaluate your weight loss and see if you need to eat more, eat less, or if you're losing as expected, stick with the 50%.
ETA: Do you have MFP and Fitbit set for the same amount of weight loss per week?
~Lyssa
Yes, I'm set for a 2lb/week loss on MFP and a 1,000cal/day deficit on Fitbit.
I weigh all my food to the gram on a food scale, and double check calorie entries with the USDA website entry. I'm confident my logging is as accurate as possible.
Okay - that's awesome!
I still think you'll be best off logging calories in as accurately as possible - which you are - give it 4-6 weeks and evaluate your weight loss at that point. Then you'll have a pretty good idea of how accurate your Fitbit's numbers are.
~Lyssa1 -
What Lyssa said.
My charge HR SERIOUSLY overestimated my exercise calorie burn. Trying to figure that out helped me to figure out my One was overestimating too. The first ever fitbit was awesome tho.
My One is being nicer to me lately tho.
But with your stats, you very easily are burning what it says you're burning.0 -
Thanks everyone for your input! Seems general consensus is to just wait it out and see, which is what I'll do.0
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How do you guys know if your fitbit is overestimeating or underestimating? my fitbit says my tdee is about 2100 cals a day and that sounds about right given I'm 5'7" and 158 lbs.0
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Colorscheme wrote: »How do you guys know if your fitbit is overestimeating or underestimating? my fitbit says my tdee is about 2100 cals a day and that sounds about right given I'm 5'7" and 158 lbs.
They know by comparing their actual weight trend to what it should be given their calorie allowance. If they're steadily gaining, Fitbit is overestimating. If the goal is maintenance and they keep bouncing between a few pounds, they've found maintenance. If they're losing at the rate they should be, Fitbit is spot on. If they're losing at a faster rate than they're aiming for, then Fitbit is underestimating their TDEE. This is, of course, based on the hope that the people saying this are actually weighing/logging every single thing they consume to the gram and even that has a margin of error. If they're not weighing their food to the gram, then they really can't say it's Fitbit doing anything wrong as much as it is their own calorie consumption.1 -
Colorscheme wrote: »How do you guys know if your fitbit is overestimeating or underestimating? my fitbit says my tdee is about 2100 cals a day and that sounds about right given I'm 5'7" and 158 lbs.
Go to your fitbit profile (website).
it will have a 30 day avg burn and intake
30 day avg burn - 30 day avg intake = avg daily deficit or surplus
avg daily deficit or surplus * 30 = total 30 day deficit or surplus
total 30 day deficit or surplus/3500 = approximate weight loss or gain
Compare that to what actually happened with your weight0 -
shadow2soul wrote: »Colorscheme wrote: »How do you guys know if your fitbit is overestimeating or underestimating? my fitbit says my tdee is about 2100 cals a day and that sounds about right given I'm 5'7" and 158 lbs.
Go to your fitbit profile (website).
it will have a 30 day avg burn and intake
30 day avg burn - 30 day avg intake = avg daily deficit or surplus
avg daily deficit or surplus * 30 = total 30 day deficit or surplus
total 30 day deficit or surplus/3500 = approximate weight loss or gain
Compare that to what actually happened with your weight
I never used that, as I use Trendweight, but I went to go do this and it lists my average intake as 0 for some reason. Has that ever happened to anyone else? I refreshed the page several times.
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shadow2soul wrote: »Colorscheme wrote: »How do you guys know if your fitbit is overestimeating or underestimating? my fitbit says my tdee is about 2100 cals a day and that sounds about right given I'm 5'7" and 158 lbs.
Go to your fitbit profile (website).
it will have a 30 day avg burn and intake
30 day avg burn - 30 day avg intake = avg daily deficit or surplus
avg daily deficit or surplus * 30 = total 30 day deficit or surplus
total 30 day deficit or surplus/3500 = approximate weight loss or gain
Compare that to what actually happened with your weight
I never used that, as I use Trendweight, but I went to go do this and it lists my average intake as 0 for some reason. Has that ever happened to anyone else? I refreshed the page several times.
It's a glitch. Seems to have been going on for the past couple weeks. Mines currently doing the same thing and there is also a few things missing from my profile page. Fitbit is apparently working on it.0 -
I read this article recently.
http://www.runnersworld.com/sweat-science/how-accurate-is-your-wearables-calorie-count0 -
I'm definitely beginning to think my Zip is overestimating calories. Lately I've been burning 750 extra calories (according to my Fit Bit) which should have me losing some weight and I'm not. I thought about making my height an inch or two shorter to give me a lower BMR and burn the calories I normally would. It's frustrating because I've been at the same weight for roughly a week when normally I can lose weight pretty consistently, even if it's 0.2 lbs here, 0.2 lbs there. My other thought was to try and burn an extra 1000 calories on top of my food intake and see what results I get. Or maybe I just need to drop my calories from 1800 to 1600-1700. Not quite sure yet.0
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I recently upgraded from the zip to the Alta, and I'm definitely getting less steps/calories burned with the Alta. I always had a suspicion the zip waay overestimated.0
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I've had a Charge HR for almost ten months and as far as I can tell it's pretty darn accurate. I think if anything it slightly under-estimates my TDEE.0
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lauraesh0384 wrote: »I'm definitely beginning to think my Zip is overestimating calories. Lately I've been burning 750 extra calories (according to my Fit Bit) which should have me losing some weight and I'm not. I thought about making my height an inch or two shorter to give me a lower BMR and burn the calories I normally would. It's frustrating because I've been at the same weight for roughly a week when normally I can lose weight pretty consistently, even if it's 0.2 lbs here, 0.2 lbs there. My other thought was to try and burn an extra 1000 calories on top of my food intake and see what results I get. Or maybe I just need to drop my calories from 1800 to 1600-1700. Not quite sure yet.
Or you could give it more than a week. Come on! 2 -
lauraesh0384 wrote: »I'm definitely beginning to think my Zip is overestimating calories. Lately I've been burning 750 extra calories (according to my Fit Bit) which should have me losing some weight and I'm not. I thought about making my height an inch or two shorter to give me a lower BMR and burn the calories I normally would. It's frustrating because I've been at the same weight for roughly a week when normally I can lose weight pretty consistently, even if it's 0.2 lbs here, 0.2 lbs there. My other thought was to try and burn an extra 1000 calories on top of my food intake and see what results I get. Or maybe I just need to drop my calories from 1800 to 1600-1700. Not quite sure yet.
Or you could give it more than a week. Come on!
I'm not someone that typically goes an entire week without any weight loss, which is why it's extremely perplexing.
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