Activity Level and "Metabolic Rate"

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glevinso
glevinso Posts: 1,895 Member
in Fitness and Exercise
Sorry this is going to be a bit long:

So I seem to have an opposite "problem" than most when it comes to working out their metabolic rates and I am wondering if anyone has experienced this as well.

Most of the time people come on here saying they eat 1200 calories and still gain weight so their metabolism must be "damaged" or some such bullpoop. This is NOT that kind of discussion.

So for the past 4 months I have been diligently tracking everything I eat, and as a consequence of training for endurance events, I track every workout with calorie burns measured either through heart rate, or power (if on the bike). One thing I have always been curious about is if the estimates for your BMR and "activity level" is at all accurate.

I built a spreadsheet that totals up all my calories consumed, calories burned, and weight lost, and tried to correlate it to my metabolic rate. Now it is rare that I take a day off of training, but I was curious what my "maintenance" calorie load is on a day I don't have a training session. In general I am entirely sedentary other than my workouts. I sit at a desk all day, and at night I sit and watch TV. I barely move. So if I set MFP to maintenance calories, for a sedentary person, it tells me I get 1960 per day (I am 5'7" and 145lbs, with a "visual guess" of about 10-11% BF - IE I have a defined 6-pack when I flex but still have a little bit of visible fat).

Now - my spreadsheet comes up differently. I am going to assume two things here: 1) that my estimate of how many calories I eat is reasonably accurate, and I have enough experience doing that to think that is a fair assumption, and 2) that my Garmin is reasonably accurate at calculating calorie burns.

In the past 15 weeks... I have eaten 262026 calories, burned 84507 through purposeful exercise and lost 14.6lbs. That works out to an average consumption of 2495 calories per day, with an average calorie burn of 805 per day through exercise, and an average deficit of 487. This would work out to a TDEE, if I was actually using that method, of 2982/day.

Now for the interesting part - this calculates out to a "maintenance" need on a "day off" to be 2177. Essentially 9% higher than MFP's estimate. If I set MFP to "lightly active" then it gives me a number closer to that 2177.

So... (finally)

Is it possible that my metabolic rate is simply higher than normal considering all I do all day is sit on my butt? Is it possible for someone to "run hot"? I should add that I am fairly twiggy and lift nothing heavy (except beer glasses). So it's not like I have a bunch of visible extra muscle that needs fuel.

Replies

  • ForecasterJason
    ForecasterJason Posts: 2,577 Member
    edited November 2014
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    I've noted a similar thing myself. MFP thinks I barely need 2000 calories (more like 1910 on a rest day), but I think my real maintenance is closer to 2200. My body fat is only 8%, so even though I don't have much muscle mass I essentially am pretty much "all muscle". (I'm similar in height to you but 20-25 pounds lighter). Having a higher muscle to fat ratio will result in a higher BMR, which I think is a major reason why calorie estimates can be low for people like us.
  • RllyGudTweetr
    RllyGudTweetr Posts: 2,019 Member
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    glevinso wrote: »
    Sorry this is going to be a bit long:

    So I seem to have an opposite "problem" than most when it comes to working out their metabolic rates and I am wondering if anyone has experienced this as well.

    Most of the time people come on here saying they eat 1200 calories and still gain weight so their metabolism must be "damaged" or some such bullpoop. This is NOT that kind of discussion.

    So for the past 4 months I have been diligently tracking everything I eat, and as a consequence of training for endurance events, I track every workout with calorie burns measured either through heart rate, or power (if on the bike). One thing I have always been curious about is if the estimates for your BMR and "activity level" is at all accurate.

    I built a spreadsheet that totals up all my calories consumed, calories burned, and weight lost, and tried to correlate it to my metabolic rate. Now it is rare that I take a day off of training, but I was curious what my "maintenance" calorie load is on a day I don't have a training session. In general I am entirely sedentary other than my workouts. I sit at a desk all day, and at night I sit and watch TV. I barely move. So if I set MFP to maintenance calories, for a sedentary person, it tells me I get 1960 per day (I am 5'7" and 145lbs, with a "visual guess" of about 10-11% BF - IE I have a defined 6-pack when I flex but still have a little bit of visible fat).

    Now - my spreadsheet comes up differently. I am going to assume two things here: 1) that my estimate of how many calories I eat is reasonably accurate, and I have enough experience doing that to think that is a fair assumption, and 2) that my Garmin is reasonably accurate at calculating calorie burns.

    In the past 15 weeks... I have eaten 262026 calories, burned 84507 through purposeful exercise and lost 14.6lbs. That works out to an average consumption of 2495 calories per day, with an average calorie burn of 805 per day through exercise, and an average deficit of 487. This would work out to a TDEE, if I was actually using that method, of 2982/day.

    Now for the interesting part - this calculates out to a "maintenance" need on a "day off" to be 2177. Essentially 9% higher than MFP's estimate. If I set MFP to "lightly active" then it gives me a number closer to that 2177.

    So... (finally)

    Is it possible that my metabolic rate is simply higher than normal considering all I do all day is sit on my butt? Is it possible for someone to "run hot"? I should add that I am fairly twiggy and lift nothing heavy (except beer glasses). So it's not like I have a bunch of visible extra muscle that needs fuel.

    Sounds to me like your exercise's intensity - which is especially tricky for MFP to gauge accurately - is higher than the default for the activity you're putting in.
  • glevinso
    glevinso Posts: 1,895 Member
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    In this case I am using calorie burn numbers from my Garmin devices. When taken using my bike's power meter it is quite accurate, since it is measuring actual power expended to move me. I reasonably trust the heart-rate based numbers gathered while running.
  • ephiemarie
    ephiemarie Posts: 264 Member
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    I don't have an answer, but what's your resting heart rate?
  • glevinso
    glevinso Posts: 1,895 Member
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    Low to mid 50s usually, unless I have had some caffeine. Then it tends to be high 50s.
  • DCDoesSeattle
    DCDoesSeattle Posts: 2
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    I suggest seeing a nutritionist who can measure your resting Basal Metabolic Rate (BMR). Depending on more factors (e.g., muscle to fat ratio, nutrition) than MFP takes in to account (e.g., age, weight), your BMR can be dramatically different than the average. The nutritionist does this reading with a device that sends pulses through your body and measures how quickly they come back. This is significantly more accurate than basic calculators online.

    By the way, your resting BMR is how many calories your body would burn if you were in a coma, so you're already burning more just by sitting up and thinking all day at a sedentary job.

    --

    On a related note, I find MFP is flawed when it comes to incorporating BMR. There's no logic-based way to set our calories goals without visibility in to how MFP incorporates it. This is why people like you, glevinso, have to resort to separate, detailed spreadsheets. I think that's a shame and hope MFP revises its approach.

    In the meantime, here's my work-around, that I hope can help you, too:
    * I input BMR every day as 'exercise'
    * I set my calorie goal to 0 and aim to keep 'remaining' calories a positive number for weight loss, or a negative number of weight gain.

    This work-around solution looks counterintuitive because a negative Net should signal weight loss. But it's the best I can do to make use of MFP's system. Once you figure out your resting BMR, I hope it helps you, too.
  • glevinso
    glevinso Posts: 1,895 Member
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    Well I am certainly not going to go see a nutritionist to satisfy a simple curiosity :)

    I know what the definition of BMR is - I am not sure what in my post made that sound confusing?

    FWIW, I haven't been tracking calories since I made this post a few weeks ago. Regardless, all your method is doing is inverting the numbers, I don't see how it is any different than the regular MFP method.

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