How accurate are your Fitbit calories?

I have my MFP set to lightly active. And my Fitbit give me no extra calories which I dont understand being I get 10k steps minimum/day and exercise 90ish minutes every other day.

Mine is 200-300 over per day

I have a fitbit Charge 2 (so it has a HR monitor function) and I tracked my intake/TDEE/weight on 2 different spreadsheets for 4 months and my fitbit's TDEE estimates are spot-on!

But I use "TDEE - intake" method to track my deficit, it just seems clearer to me. I can't seem to sync my fitbit to mfp anyway. Mfp always tends to overestimate the amount of exercise I did based on my fitbit.

Mine is pretty much right on the money. I don't look at the remaining calories MFP tells me, I just use it to log the food and then rely on Fitbit for my burn (I shoot for 1000 calories under my total burn per Fitbit). I use Libra to log my weight and calculate weightloss stats, such as average daily deficit based on weightloss over the last x number if months and the average it tells me is just over 1000 Cal day for the past 3 months.

I've had my Fitbit synced since mid-2015 and have found it to be very accurate. I eat back 100% of my adjustments and lose/maintain as I would expect.

Christismylife wrote: »

If you have a Fitbit (I have the charge 2) and have it sync to MyFitnessPal to calculate your daily exercise calories, how accurate do you find them to be?

I have my account set at the lowest activity level and my Fitbit syncs to add in exercise calories. I find the calories it gives me to usually be high compared to what I might have given myself for my exercise for the day. I wonder if this means the calculations are off or if I am more active most days overall than I realize.

Your FitBit isn't just giving you more calories for exercise...it is adjusting your calorie target based on all activity in comparison to your activity level setting. Most people I know aren't truly sedentary, even with desk jobs.

My FitBit jives pretty close with my own data

I've had a Fitbit Alta HR since last December and have been manually keeping track of calories in and out (Fitbit vs Actual Weight Loss/Gain) daily and monthly. I have found that my Fitbit has been consistently 400-500 calories overestimating each day (calorie burns between 2050-2400 while my manual calculations based on actual weight gain/loss are closer to 1600-1900). I never rely on it for daily calorie burn - my manual calculations are much closer to reality.

I'm not sure why mine are so far off - wish they were right - I'd love to eat 2400 calories/day!

I have a Garmin forerunner and I am really doubting the calories it gives me. How do you get it to track more accurately? I have MyFitnessPal set to my estimated BMR so that all calories clocked back through walking and excercise should be eaten. But it’s telling me to eat 2800 calories! I barely make 5k steps most days (very busy desk job and I’m trying to improve by walking on my 1/2 hour lunch break now) and I lift weights 3x a week. I’m definitely obese in my hip waist measurements (waist is 102 across my navel but my hips are 99! BMI 21). I want to lose fat and increase my lean muscle mass so I’m completely lost.

I've been using one for 3 weeks and so far the math is working pretty closely -- they estimated 2.5 lbs a week with my usual daily deficit and that's exactly what I've lost each week. So, at least going by me, works pretty darn well so far.

Keep in mind what information the fitbit is collecting. How often your arm moves, the rate of movement of that arm, and your HR. With that limited data it cannot be perfectly accurate for determining energy consumed. Correlating that data to distance is not overly complex. Energy consumption is much more challenging because it involves the fitness level of the subject, energy on board, and other factors. The device is using that data and the results from heaps of scientific studies to try to give you the calories consumed based on your personal stats. When it comes to energy consumption we are all somewhat of special snowflakes. That is why some stay thin easily, and some pack on the LB's. I think 20% could be a reasonable target. A great device, but it needs to be calibrated for an individual based on tracking over a period of time.

From Fitbit site:


In case interested here is a report to achieve how the energy consumption can be measured for an athlete where a high degree of accuracy is necessary: https://pdfs.semanticscholar.org/751c/7b4dec47f8c5da324f2b782df837dc33bf77.pdf

Abstract:

GottaBurnEmAll wrote: »

It should be noted that Fitbit measure jolting or impact, not casual arm movement.

If you applaud with it on or shake out laundry, it will measure that as steps, for example. There needs to be some impact accompanying the arm movement for it to register as a step.

This is why I've started taking mine off while doing the washing -_- was giving me too many steps

Lets consider this in perspective shall we?

You are wearing a relatively inexpensive mass produced consumer device that is calibrated to be close for a wide range pf people in your age/gender/weight range. This device uses proxy measurements to determine calorie burn rates. Steps are measured by arm movements and jolts, calorie burn rate is measured in part by heart rate.

Lots of places that errors can creek into the calculations but you then compare the results to high end scientific equipment that takes trained technicians to operate and produce results, individual tests will cost you more than your fitbit.

IF that gives you results in about 10 to 20 percent of actual then I’d say that is pretty good.

I use my Fitbit to ensure that I achieve my minimum desired burn, not so much in the actual calorie burn shown but to compare today with yesterday with tomorrow. A higher number one day means I burned more calories than the previous day. This is only accurate as long as I am doing similar exercises. I get a indicated burn of 300 calories for a brisk 30 minute walk but only 200 calories for a 30 minute fast swim. Obviously a swim ay will have lower indicated calories than a walking day even if the actual burn is identical. I take that into account when comparing swim to walk days.

Of course we then compare the indicated burn rate with our logged calorie intake. Remember that the labeled nutrition numbers can be out by 20% according to a very toothless law. There is no penalty for any food manufacturer misstating the calorie content in their foods.

If we are using raw foods, how many calories in an apple? In an egg? If you look at the MFP numbers they are all over the map. Even using the US government official numbers there is room for some variation, how big an egg or apple? Even same sized eggs and apples will have different nutritional contents depending on what the chicken ate or what variety of apply you have.

I simply use the numbers for either food or burn as a rough guide knowing that there are numerous sources of errors in them , some of which I know and can adjust for some of them I don’t know or don’t have any idea of the magnitude or direction of these errors.

I take the indicated burn and subtract 10%, I take in calculated food intake and add 20%. No real reason for these numbers but in my case they seem to work. I then aim for a 500 to 750 calorie gap and that comes close to my actual weight loss over time. ( i.e. a kg every 10 days to 2 weeks or so)

Remember the scale also has lots of errors in it so I simply use the 7 day moving average for weight, muscle mass and body fat composition.

All this is just to assist in reaching my desired goal and that is to like what I see in a full length mirror every day. That is the only result that I really care about, everything else is simply to assist me in getting there.