Using BMR to lose weight.

[PLURmedic]

I went to my local fitness facility and did a metabolic test and they calculate your RMR and it was 1955kcal. On average during my day at work and what not I burn around 552 and I also excercise daily which usually burns up an addition 500 or even more depending how i'm feeling. So I burn up about 1050+1955(rmr)=3005 per day, sometimes it varies especially on the weekend. How much should I be eatting to ditch some weight? 3005-500/1000?

[SunsetRunner · Accepted solution]

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@PLURmedic wrote:

I went to my local fitness facility and did a metabolic test and they calculate your RMR and it was 1955kcal. On average during my day at work and what not I burn around 552 and I also excercise daily which usually burns up an addition 500 or even more depending how i'm feeling. So I burn up about 1050+1955(rmr)=3005 per day, sometimes it varies especially on the weekend. How much should I be eatting to ditch some weight? 3005-500/1000?

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Let's say your BMR is 2,000 less 500 (to loose 1 lb. per week) leaves 1,500 to eat, plus

exercise of about 1,000, equals 2,500 to eat (or eat less, and lose more than1 lb. per week).

[PLURmedic]

Got it, thanks for the clarification. The employees there did a horrible job at explaining it.

[SunsetRunner]

When not hungry, try not eating more even the plan can say there's hundreds of calories left to eat. When our bodies have all nutritients it needs, it can be perfectly happy with less.

[Heybales]

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@PLURmedic wrote:

Got it, thanks for the clarification. The employees there did a horrible job at explaining it.

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Actually, that's not correct at all either.

BMR is calorie burn if you slept all day.

RMR is calorie burn if you sat in chair like you did during the test all day.

You do NOT take a deficit from that to lose weight. Because obviously you burn much more than either of those amounts daily.

You take a deficit just as you were attempting to calculate, from what you burn in total each day.

But you can't really hope to get good estimates from either daily activity or exercise separately.

But guess what is attempting to do that daily.

Ya, Fitbit.

What you could do with your measured RMR though is tweak Fitbit so it's using the correct RMR compared to the calculated BMR it starts with.

Looking at your daily calorie burn graph per 5 min blocks.

What is the burn during sleep and non-moving times per 5 min?

Divided by 5 is your per min, x 1440 is the BMR they are using.

What is your age, weight, height?

I've got a spreadsheet with formula to tweak the height in their stats so they come up with a BMR that matches your RMR from the test.

That will make your daily burn estimate more accurate.

Then you merely eat less than that figure by reasonable amount to lose fat weight.

Make it unreasonable to include some muscle mass.

[PLURmedic]

That a lot of info lol. I'm 30, 6ft and currently 208lbs. Graph says 20calories when im asleep per 15min

[Heybales]

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@PLURmedic wrote:

That a lot of info lol. I'm 30, 6ft and currently 208lbs. Graph says 20calories when im asleep per 15min

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So Mifflin BMR (which is close to what Fitbit uses) based on your stats is - 1941

Fitbit is using 20/15 x 1440 = 1920 as BMR

And if you used the 5 min graph amounts, probably even closer.

So the calculated RMR that would go along with that BMR is - 2101

Your tested RMR is 1955.

The BMR that would go with your tested RMR is 1799. About 140 lower than what Fitbit is using.

So within 7%, probably just related to the fact the calculated BMR/RMR start inflating above healthy weight.

Could be some related to slightly less muscle mass than expected for average ratio.

Or could be you've been in a diet for awhile and suppressed your system.

Close enough so nothing to worry about hopefully.

If you wanted to change the height on Fitbit so it used a BMR closer to your RMR, it would be 67.9 inches tall. So minor difference to correct for that 140 calories.

But then you'd want to have a manually corrected stride length, since they base it off height and gender, and 4 inches shorter with corresponding shorter stride length could add up.

[PLURmedic]

According to my dashboard I burn an average of 4124 calories a day. It ranges between 3500 and 4500 a day. Should I just remain 1000 cal below whatever fitbit says or stick to 2000 regardless?

[Heybales]

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@PLURmedic wrote:

According to my dashboard I burn an average of 4124 calories a day. It ranges between 3500 and 4500 a day. Should I just remain 1000 cal below whatever fitbit says or stick to 2000 regardless?

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If you got over 60 lbs to go, set Fitbit to the 1000 cal deficit, and hit your eating goal daily.

If you are willing to miss it under on big burn days, be willing to go over on small burn days.

Constantly under by too much isn't going to help your body want to lose just fat or not get stressed out and cause issues.

As a guy we luck out better anyway, but can still be effected.

Your big burn daily routine also helps out, since low key that means it's mainly fat burn, unless eating constantly.