Resting Metabolic Rate

[Bromey757]

I recently have gotten my RMR tested. I would like to enter that information into the fitbit app for bette accuracy of caloric burn. But there is currently no field to enter that information into.  Does anybody know if this will be a future option or am I missing something on the app.

[JohnnyRow]

That option is not currently available.  Nobody here would know if it is coming.

Out of curiosity, how much different was your measurement from what Fitbit uses?  You can see what Fitbit is using by looking at calorie burn chart overnight while asleep, or looking back in history to before you started wearing a Fitbit.

Keep in mind, your BMR (or RMR) changes as your weight changes.  Fitbit's calculation makes that adjustment as long you are tracking your weight.  I'm not sure how it would or could be handled if you could input it yourself, unless you went back and got retested.

[Bromey757]

I tested earlier in the year at about 2190 cals per day.  Fit bit has me at 1800. I am a lifter with apparently a fast metabolism. Like you said its based on weight. Does fitbit take into account weight vs. Lean tissue? Hopefully not bmi. Which can be very inaccurate for active individuals. 

I usually get dexa scanned as well. Up for another one shortly.

[t.parker]

@Bromey757 Fitbit takes into account weight, age, and gender. I assume, you probably think of using the Katch Mcardle formula which takes into account LMB. It would be great if Fitbit implemented a different BMR calculation method (as an option for people who would like to use it). I wouldn't however use this method as default because most people don't know their LBM and even if they use smart-scales, the results are usually quite inaccurate. Considering, that majority of Fitbit users bought their devices to support weight loss, such potential inaccuracy may completely destroy their efforts. Hence, it's safer to use the lower generic BMR calculated just from age, weight, and gender. I know that Garmin does such adjustment additionally taking the level of activity into account but not LBM. This gives me an additional 200kcal comparing to basic formulas. However, there are lots of complaints because of that as for many users such BMR is way too high (you can't really take everyone and describe using a single equation).

You may try to post a suggestion to include either custom BMR or add different computation methods in the Feature Suggestion forum. It may or may not happen one day 🙂

[Bromey757]

 I will look into the Katch Mcardle formula. As for smart scales im not on board. They have been off from my experience. I believe the most accurate method of measurement of lbm/bf is dexa. When I dexa i also 7 site pinch to get good reference. Dexa is said to be accurate to within 1%.

[t.parker]

@Bromey757 that's exactly the point. Now, you are in minority among Fitbit (and not only) users who are well aware of their LBM and RMR. Notice that many users use Fitbit Aria scale and others which can sync with Fitbit account. Taking this data to compute BMR would be trivial but considering how inaccurate such scales are it could provide extremely wrong BMR for majority of users. Usually, the athletes make use of more accurate data because they know how to. Fitbit IMHO doesn't really target athletes but casual users. I use KM formula with applying some reduction to it to be on the safe side. The reduction coefficient came up for me experimentally. I haven't been using Dexa but calipers for accuracy. This works for me and whatever the apps say it doesn't matter so much. Unfortunatelly, there is no better solution than do everything by yourself 😄

[Jean2109]

Really but was that so ??

[Bromey757]

Lol. You are correct. The data they use does help me nail down my burn to within some degree of accuracy.  I am in construction and a lift 3-5 times a week.  Due to my activity and lack there of some days I have huge swings in burn. From 3500 to 6000 a day.  Some days at work are just more laborious and active.

  If I am trying to achieve a 500 call deficit a day I lose weight consistently at a slow rate. I usually don't keep up correctly on the massive 6000 calorie days.  Of course if I have too many of those days I'll begin to lose lbm. 

  Always trying find more accuracy. I'll begin to look into the km to help fine tune. Thanks for the dialog. Great info.