Trying to learn my TDEE from my Fitbit, unrealistic or not?
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MinmoInk
Posts: 345 Member
The main reason why I started using Fitbit was because I would like a better idea of my TDEE. I've been seeing threads all over the place in regards to people saying yey and nay for measuring calories spent throughout the day. I've used MFP for many years and have succeeded in weight loss and I'm setting myself up for maintainence and I would just like to know how active I am day to day and how much I should eat to maintain, etc.
I understand that linking MFP to Fitbit gives an unrealistic calorie adjustment on MFP, but is it safe to be "on target" in Fitbit calorie estimation by the end of the day generally? I track food on MFP, exercise on either Fitbit or Runkeeper, and I follow a 500/250 calorie deficit on Fitbit (I'm currently trying to lose my last 6~ lbs). I own a flex.
I understand that linking MFP to Fitbit gives an unrealistic calorie adjustment on MFP, but is it safe to be "on target" in Fitbit calorie estimation by the end of the day generally? I track food on MFP, exercise on either Fitbit or Runkeeper, and I follow a 500/250 calorie deficit on Fitbit (I'm currently trying to lose my last 6~ lbs). I own a flex.
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You described the reason I got a fitbit in the first place. Kept it and used it religiously for 6 months. The entire time it was vastly overstating my TDEE.
Use this calculator here which is by far the best I've found: http://www.muscleforlife.com/macronutrient-calculator/
It not only calculates TDEE accurately, but you can also use it to figure out what your macros should look like.
I sold my fitbit.0 -
WilsonFilson wrote: »...
I sold my fitbit.
Wow that's extremely unfortunate and discouraging ugh... I don't want to go balls to the walls with TDEE calculators because my activity level varies wide from day to day and it's never consistent. To me that's just how I live life so as far as "activity level" goes it changes from week to week, day by day and the time of year, weather, etc. I have a guesstimation on my TDEE from previous calculators and how it could range but I hate being in the dark and stressing out about CICO so much when I just want to start maintaining a balanced life. I thought Fitbit could do this.0 -
There was a study published in the journal JAMA Internal Medicine (a peer-reviewed scientific journal) recently that found most trackers (they tested 12 devices, including Jawbone and Fitbit products) underestimate calorie burn compared to the metabolic chamber method over a 24 hour period (which is considered a "gold standard" in metabolic measurements).
The same study found that ALL trackers under-estimate calorie expenditure over a 15-day period using the doubly-labeled water (DLW) method. The DLW method is used to capture calorie expenditure over a longer period of time through normal daily events.
From reading the study, I get the impression that this is the opposite of what the researchers wanted. First, they explained that the lower calorie burn calculated by trackers was due to participants not wearing them while showering and while charging the batteries. This seems logical when looking at the range of variance (278 lower to 204 higher with metabolic chamber method and 590 lower to 69 lower with DLW). But then the researchers concluded that such trackers aren't accurate at all. Based on the data presented, the collection methods, and the explanation for variances, I can't see how they came to that conclusion.0 -
Midwesterner85- wow that's pretty insightful. I have been wondering how Fitbit trackers do without HRM given that I get cold and shiver a lot, that isn't taken to account etc etc which is why I'm baffled how people get "way over estimations" for their Fitbit tracking. I mean measuring movement isn't the only way we burn calories throughout the day so I'm very confused why some people have stated that Fitbit is way off. I mean how can it be way off? We should be doing a lot more with calories in a day to day basis if we interact with the weather, the way we interact with food (cold, hot) and our individual body makeup.. Technically Fitbit should always be lower right? I guess that maybe Fitbit and other trackers may give out more calories for movement than we actually spend moving to make up for this difference?0
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Most of us use anecdotal evidence from our weight loss journey to form our conclusions about any number of things. You will likely find a lot of people who claim that Fitbit overestimates calories by a lot because they eat back their calories and don't lose (or they don't eat back and don't lose as quickly). The problem with that logic is that it ignores all of the other factors used by MFP - both system calculations and user inputs.0
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Thanks Midwesterner85 for giving me a different viewpoint entirely!
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Mine seems to calculate it just fine. Each person is different I guess.0
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amelia_bedelia86 wrote: »Mine seems to calculate it just fine. Each person is different I guess.
True this! I've also decided to change my MFP activity level which has offered much more realistic caloric adjustments 0 -
You might want to read the FAQ in the stickies - especially the 2nd half on the consequences of setting a higher MFP activity level and what happens to end of day estimates of eating goal.
While setting activity level to something more honest keeps the adjustments lower and perhaps allows better planning - I've found that vast majority of people don't vary their calories on breakfast or lunch that much anyway - so the point is moot if there is any inkling to what the average day calorie burn is going to end up being.
Planning is easily possible.
The adjustment then comes in useful as to how much can be had for dinner or snack or dessert, ect. And end of day is just fine for that.
To add to midwesterner's excellent thoughts - other case studies (where 1 or 2 people are followed so not research study of a group) have shown it also depends on how much exercise you do and what type.
And if daily activity involves standing or effort but not many steps.
A type it's not good at estimating, done a lot, is going to throw it off a lot.
The majority of people with these devices are doing walking, maybe some running. For them and that activity - just fine. Probably more inaccuracy in their food logging or even nutrition labels for that matter.
But especially the early devices that were step based - wrong workouts are badly underestimated. Elliptical hard effort, spin bike, ect. Those things that could be done a frequently for a long duration - and that adds up.
The HRM devices can be fooled like any HRM though, and that's besides the fact it may not even be reading accurately for you and perhaps intense exercise, missing beats or faster beats.
So the calorie adjustment on MFP is just fine. This has nothing to do with possible inaccuracies in MFP's exercise database after all, nor just your workout anyway. (which frankly it depends on the exercise and intensity anyway - could be right on).0 -
WilsonFilson wrote: »You described the reason I got a fitbit in the first place. Kept it and used it religiously for 6 months. The entire time it was vastly overstating my TDEE.
Use this calculator here which is by far the best I've found: http://www.muscleforlife.com/macronutrient-calculator/
It not only calculates TDEE accurately, but you can also use it to figure out what your macros should look like.
I sold my fitbit.
That's nothing more than the good old Harris research study from 1919 TDEE table, but using the Katch BMR calculation - which does help a bit compared to Harris BMR.
As to say most accurate is a stretch though.
Is 3 hrs of walking equal to 3 hrs of running equal to 3 hrs of lifting a week?
What if I carry mail 6 hrs a day and then workout 3 days a week for 1 hr - compared to me equal weight/BF% counterpart with a desk-job and no kids that does the same workout?
Really - same TDEE?
Ya - accuracy has a lot to be desired unless you know how to use that tool well beyond their explanation.
While some could indeed end up right in the range - there are more odds you won't be near it.0 -
WilsonFilson wrote: »You described the reason I got a fitbit in the first place. Kept it and used it religiously for 6 months. The entire time it was vastly overstating my TDEE.
Use this calculator here which is by far the best I've found: http://www.muscleforlife.com/macronutrient-calculator/
It not only calculates TDEE accurately, but you can also use it to figure out what your macros should look like.
I sold my fitbit.
That's nothing more than the good old Harris research study from 1919 TDEE table, but using the Katch BMR calculation - which does help a bit compared to Harris BMR.
As to say most accurate is a stretch though.
Is 3 hrs of walking equal to 3 hrs of running equal to 3 hrs of lifting a week?
What if I carry mail 6 hrs a day and then workout 3 days a week for 1 hr - compared to me equal weight/BF% counterpart with a desk-job and no kids that does the same workout?
Really - same TDEE?
Ya - accuracy has a lot to be desired unless you know how to use that tool well beyond their explanation.
While some could indeed end up right in the range - there are more odds you won't be near it.
While this is my own anectodal evidence, note that once I stopped relying on my fitbit to determine tdee, and used the calculator I provided above, I dropped another 4% body fat within 2 months. I'm at 11% right now. Before that I was on a 3-month plateau (and no, not eating all of my calories back), because fitbit was telling me I was burning way more than I actually was.
Of course, there are a lot of factors involved (type and amount of exercise, etc.), but I found that it is most consistent to find a solid TDEE calculator and find the right average activity adjustment. Maybe your activity varies from day to day, but that doesn't matter if the average is close to what goes into the calculator. Additionally, after you start using it, its recommended that you make tweak adjustments (more exercise or less food) from time to time based on what you are seeing on the scale.
Once you hit BMR, start reverse dieting back to your TDEE and then start cutting again. This is the key to long-lasting weight loss without having to always be eating at an incredible deficit. But that's another topic for another thread I guess.0 -
So good, you did indeed use the tool beyond their explanation of it - a rough starting point, adjusted as needed.
Same can be done with the Fitbit for vast majority of people, adjustment may be necessary - or finding out what in your routine is causing it to be so off. Could be fixable, could be purely because off the averages that must be started with.0 -
@MinmoInk : Why not just test it yourself? The accuracy of Fitbit's TDEE estimate varies from person to person. For some it overestimates, for some it underestimates, and for a few it is almost dead accurate. However, it should, for anyone, give a relative level of activity that can be used as a guide in adjusting calorie intake.
To test it, use it for a month, connected to MFP. During that month, log your food as accurately as possible - weigh every bite. Then, after 30 days, you can look at the graph of intake vs. burn on your Fitbit profile page. It gives average intake and average burn there. From those numbers, compute your expected weight change. Compare that to your actual weight change and you've got a pretty good idea of how Fitbit's estimate of your TDEE compares to your actual TDEE.0
