Heybales - another SS question. Fitbit ht adjustment?

skbarton

I was playing around with the newest version of the spreadsheet (10/30/13) as it has an updated Fitbit adjustment. I'm guessing it is to account for the female adjusted TDEE compared to male. Before this latest release, the SS indicated I should decrease my height 5 inches or so. The newest version suggests increasing my height by 7". BMR calculation hasn't significantly changed between versions.

Wouldn't the increased height increase the FB calculated TDEE?

heybales

I was playing around with the newest version of the spreadsheet (10/30/13) as it has an updated Fitbit adjustment. I'm guessing it is to account for the female adjusted TDEE compared to male. Before this latest release, the SS indicated I should decrease my height 5 inches or so. The newest version suggests increasing my height by 7". BMR calculation hasn't significantly changed between versions.

Wouldn't the increased height increase the FB calculated TDEE?

So Katch is higher than Mifflin BMR?

Prior to last version had correction to FitBit formula that introduce an error actually, parentheses in wrong place, only effected some results, yours it must have.

Actually, it's not a comparison between Mifflin and Katch BMR. It's comparison of Mifflin to an avg of Katch and Cunningham.
Because all your non-moving time is not asleep, as BMR would be used for. On average, probably half your non-moving time is awake, which would be RMR. That could be 150 to 250 cal difference.
But since FitBit only uses one value for non-moving time, the only way to get that close is take average.

So the height adjustment is to get your FitBit BMR to equal the average of Katch and Cunningham.

Sadly, the studies on differences between metabolic burns with men and women was looking at sedentary TDEE, just no exercise, but not BMR or RMR level either.
So the reduction was based only on non-exercise TDEE, so I can't really adjust for that on the FitBit tab, which only deals with BMR.

Nope, you are seeing the difference in bad and good formula writing.

LH85DC

Hi Heybales- I had a similar question.

So on the original copy of the spreadsheet that I used (dated 5/7/13), I put in all of my information and got:
Katch BMR (based on BF%) 1375
Mifflin BMR 1350
Adjust Fitbit height to 67.59 inch (I'm actually 64 inches)

Then the update came out (10/28) and I got the same BMR figures, but it told me to increase my height to 70.2 inches- which seemed to make my calorie burns really high for what I was doing (walking).

Then this morning I was looking at the newest update (10/30), and found that the FitBit_BodyMedia tab will no longer calculate my Katch BMR, because it is now based on 'tested RMR'- which I don't know.

What I'm confused about is how to set my FitBit. My numbers at the original height adjustment (67.59) seemed about right- that was how I calculated my TDEE for my 6-week reset. For my reset, I gained a pound and a half in the first two weeks, then maintained within 1 lb of that weight for the next month- so it seemed pretty accurate.

Should I just continue using that original calculation since it seemed about right? the extra 3 inches on the 10/28 spreadsheet had me averaging almost 200 calories more a day for that week- that just seemed too much higher, so I reset it back to the 67 inches.

Also curious to see what the newest version would give me if it had the BF% option for Katch instead of tested RMR... does RMR give a better calculation for that?

heybales

Hi Heybales- I had a similar question.

So on the original copy of the spreadsheet that I used (dated 5/7/13), I put in all of my information and got:
Katch BMR (based on BF%) 1375
Mifflin BMR 1350
Adjust Fitbit height to 67.59 inch (I'm actually 64 inches)

Then the update came out (10/28) and I got the same BMR figures, but it told me to increase my height to 70.2 inches- which seemed to make my calorie burns really high for what I was doing (walking).

Then this morning I was looking at the newest update (10/30), and found that the FitBit_BodyMedia tab will no longer calculate my Katch BMR, because it is now based on 'tested RMR'- which I don't know.

What I'm confused about is how to set my FitBit. My numbers at the original height adjustment (67.59) seemed about right- that was how I calculated my TDEE for my 6-week reset. For my reset, I gained a pound and a half in the first two weeks, then maintained within 1 lb of that weight for the next month- so it seemed pretty accurate.

Should I just continue using that original calculation since it seemed about right? the extra 3 inches on the 10/28 spreadsheet had me averaging almost 200 calories more a day for that week- that just seemed too much higher, so I reset it back to the 67 inches.

Also curious to see what the newest version would give me if it had the BF% option for Katch instead of tested RMR... does RMR give a better calculation for that?

That's strange, I just tested the current version, got rid of the RMR in the yellow field on FitBit tab, and it recalced the Katch based on LBM, not on RMR. So that still works.

RMR is better option, as that means a tested value for resting metabolism, merely translated to matching BMR for use in the calculations everywhere. But if you don't have it, that's fine too.

Are you using Google sheet or download as Excel? It does work correctly, tested RMR is not required, merely available.

Newest tab has newer formula, which I kept in same format basically as the Mifflin formula for easier site reading, is more trustworthy. It using the already converted metric weight from Simple Setup tab. Old formula used displayed values, converted, math, converted again, ect. Lot of rounding differences were showing up too.

I don't have example from the prior to 10/30 version to look at, but it was an actual mistake like i said before and should be skipped. Your 5/17 version is improved also with less rounding differences.

Please reread above as to the comparison, Mifflin to average of Katch and Cunningham. Your average is going to be higher than Katch BMR, so the difference is greater than just 25 calories that it's trying to adjust for.

Take your gender, age, weight, and changed height to any BMR calc that uses Mifflin (Scooby has that option on Most Accurate link), and see what BMR it displays. It should equal (Katch BMR + Cunningham RMR)/2

If the burns for moving time changed, then you need to adjust the stride length from their default - which is based on height (which is now not real height).

The height change to get their BMR closer to reality will only affect the non-moving time.

Moving time is still based on formula's for step based activity.

And to get a sense of what real accurate would be walking 2 - 4 mph flat, look at NET results here, I think FitBit would display NET results, though they could be showing Gross results too.
http://www.exrx.net/Calculators/WalkRunMETs.html

skbarton

So Katch is higher than Mifflin BMR?

Prior to last version had correction to FitBit formula that introduce an error actually, parentheses in wrong place, only effected some results, yours it must have.

Actually, it's not a comparison between Mifflin and Katch BMR. It's comparison of Mifflin to an avg of Katch and Cunningham.
Because all your non-moving time is not asleep, as BMR would be used for. On average, probably half your non-moving time is awake, which would be RMR. That could be 150 to 250 cal difference.
But since FitBit only uses one value for non-moving time, the only way to get that close is take average.

So the height adjustment is to get your FitBit BMR to equal the average of Katch and Cunningham.

Sadly, the studies on differences between metabolic burns with men and women was looking at sedentary TDEE, just no exercise, but not BMR or RMR level either.
So the reduction was based only on non-exercise TDEE, so I can't really adjust for that on the FitBit tab, which only deals with BMR.

Nope, you are seeing the difference in bad and good formula writing.

Thanks for the explanation. Yes, my the SS has calculated Mifflin as 1301, Katch as 1340 and Cunningham as 1488. Playing at Scooby shows the adjustment to 68". I messed around a bit more and found if I adjust my height up to 63.3", the Mifflin BMR will equal 1340. I've had some decent results believing my BMR to be 1340 the last couple of weeks, so I think it would be reasonable to change FB to 63.3" . I don't really eat to the TDEE indicated by FB - I have been primarily operating off the simple set up tab, but I like to cross-reference.

You mentioned in your response to LH8 you don't have examples prior to the newest 10/30 version. I do have saved excel downloads of 4/24/13, 10/18/13 and 10/23/13 if you need other versions.

heybales

Well, I know the correct from 10/18 to 10/23 to 10/20 was what I mentioned. Digging in to the original formula, I can't believe how convoluted I made it.

If in the 10/18 and 10/20 spreadsheet, FitBit tab, could you just copy the formula from cell F28 and message me it. I have an original, it was those inbetween correction ones that I never saved, because I caught the error too quick.
But at some point I made the formula easier to look at and understand, and got rid of the rounding differences by original figures.

LH85DC

Thanks Heybales. Sorry, unfortunately I don't have any of the intermediate spreadsheets, just the original, 10/28 and 10/30.

I figured out why it wasn't updating I think- it was because I tried to just copy the fitbit page into my old copy. It's still giving me the 70.2 inch adjustment for height. It still seems high, but I'll give it a shot for a while and see what it comes up with.

Thanks again!