FitBit question for Haybales...

rhoda003

Morning,

I have been reading your responses for others about the spreadsheet. I've filled it out as thoroughly as possible (only missing my tested RMR).

I have a quick question about creating the FitBit adjustment. When I enter my information from the simple tab (BMR, activity, etc) it says that I should adjust my height to over 84 inches (7 feet tall...really?) Is that right? I put in 6' 2" for now...just because 7 feet sounds crazy

Also...I did my best to enter in my movement, walking, lifting on the simple tab...then I went to the TDEE page and entered my average calorie burn for a random week on FitBit and it gave me a standing time to enter of over 82 hours. Just want to make sure my numbers aren't wonky

I walk between 8,000-11,000 steps a day. Lift heavy 3 times a week (about 40 min). Yoga (easy) once or twice a week. Currently, I am 193 lbs and 5' 5". 36 years.

Thank you

Rhoda

GoGoGadgetMum

Funny thing is I have always overlooked that piece...yay I've just grown 20cm short no more

perky12415

except from what I gather that height adjustment is important to make the fitbit more accurate in calculating the BMR

heybales

So those adjustments are as stated, to deal with the fact the FitBit is using a BMR calculated on gender, age, weight, height, and average fat to LBM ratio those formulas assume.

But the spreadsheet, if you did the measurements for bodyfat calc and used that figure in the BF% cell, is basing BMR on your LBM, found to be much more accurate.

So to make the BMR based on age, weight, height match the better one based on BF%, only 3 things to adjust. Age doesn't change the value enough. Weight is used for calculating all moving time, so can't change that. Which leaves height as the only value to change. That does mess up default assumed stride length, but that's easily correctly in the settings.

So depending on how much you workout, your BMR is used for all your non-moving time, that could be upwards of 2/3 of your day easily. If one BMR is over the other by 200-400 calories (which I've seen many times), then your TDEE is inflated by same amount.
Take a 500 cal deficit off an inflated figure, you really only have 100 cal deficit from reality.

What's the difference between your Mifflin and Katch BMR as shown?

Now, what is actually compared, is the average of your BMR and RMR, since the devices use the same lower value for time that is awake and should be higher, I averaged it.

For the estimate of standing time, did you only enter in non-exercise days?
You'll notice that Method 3 is only if you want true TDEE Deficit method, same value daily. That is basically getting the activity calculator to match what your FitBit has already come up with.
But that's the perfect use with your workout - lifting and yoga won't be reported correctly by the FitBit. The steps would.

Now, with a change to your height, and going up, that means your TDEE is going to go up, so even that value won't be true in about a week.

And 82 hrs is not that much. It just means that line doesn't increase the calories fast enough to match your increased daily activity. it's merely a means to raise the base activity level higher to match what your FitBit is seeing.

chuckles9189

This post just made me redo lots of things. and I'm glad for it.

Haybales you are totally awesome. If I knew you, I would send you cookies.

or well-balanced meal since, you know, it's MFP.

athenalove46

Wow. Thanks for this post. I had no idea about these adjustments to make to the Fitbit! Man...

I agree with Chuckles, Haybales! You are AMAZING!

rhoda003

Thank you!
Even though my brain knew why the height needed to be changed...7 feet was a visual shock

I am so thrilled to have all this information in one place.

Thank you for being so thorough

Rhoda