calories burned varies more than you might think

zebasschick

so i use a fitbit to count steps, an older polar to track heart rate, and i log in MFP plus i've used map my fitness and some other apps, as well. no two of these give the same calories burned for the same exercise, heart rate and duration.

but wait - there's more!

when i was in worse condition, i burned a lot more calories doing the same exercises/intensity duration. i lost weight much faster then. now, i'm in much better condition, i burn a lot less calories and have to work harder to get my heart rate up. and working out longer and harder isn't leading to weight loss any more, or if it is, it's very minimal.

back when i was in worse condition, the MFP numbers seemed pretty accurate, judging by my weight loss. nowadays, my polar heart monitor - which gives only about one third of MFP and MMF - seems to be accurate. and fitbit seems to fall closer to MFP but lower. one exercise bike comes in close to my polar where the other comes up double the calories for the same workout but still well below MFP and MMF. previous bikes and treadmills give me even higher calories burned.

no fitness tracker or app is perfect when it comes to calories burned, and many exaggerate a LOT. if you use any one for a while, you'll learn to figure out how close it is and adapt to those measurements. it appears my MFP calories are about 3x higher now than my actual burn, so i plan to start eating accordingly.

btw, i do weigh all my food and log using accurate database entries. none of my drinks (mostly water or fizzy water or calorie free water enhancer popsicles) have any calories.

tomcustombuilder

The more you suck at a sport or activity the more calories you burn

zebasschick

tomcustombuilder wrote: »

The more you suck at a sport or activity the more calories you burn

well, depending. you could suck because you're not putting in much energy or running fast enough...

AnnPT77

Yeah, it's complicated.

Someone who's less fit can't reach as high an intensity (burn as many calories per minute) as someone who's more fit. The less fit person also can't hold any given intensity for as long a duration as the more-fit person. In both those ways, the more fit person can potentially burn more calories.

Some sports, a person can waste a bunch of effort that doesn't go into objective intensity (such as speed). Other sports have a narrower band of efficiency, so there's not as much wasted effort by someone who's not good at that thing. Wasted effort may not be seen by an exercise machine's calorie estimate, but the wasted effort still burns calories.

The same objective intensity (such as running pace) will feel easier to the more fit person. But a heart-rate based estimate may give more calorie credit to the less fit person because it takes more heartbeats to deliver the same amount of oxygen. It's the oxygen consumption that better correlates with calorie burn; heart rate is just a limited proxy.

Generally, someone at the same weight doing the same exercise for the same duration at the same objective pace and the same skill-based efficiency is going to burn roughly the same number of calories, fit or unfit. It's the work in the physics sense that burns the calories, not how hard the work feels.

Some estimating methods are better for some activities, but bad for others. If a person uses a consistent estimating method, and has a somewhat regular workout schedule, the normal process will work, i.e. comparing expected loss to actual loss, and adjusting calorie intake. In that scenario, for an average person working out a half hour or hour a day, the magnitude of error in exercise estimates is a fairly moderate thing in the overall calorie picture. A workable estimate is plenty good enough.

zebasschick

AnnPT77, i agree that "A workable estimate is plenty good enough", but a lot of people on these forums don't grasp that it's all approximate. i read their threads asking for an app, fitness watch or something else that will give them absolute numbers almost every day, which is why i made this post - to let people know there is no solid, absolute numbers or perfectly accurate calorie burn; it's all estimates, and you have to know your own body to figure part of it out.

starting out, i'd consider any calorie burn count as a starting point and use it to figure out more from there.

westrich20940

Yes, to all of this. I also used ~3 sources of info (Polar HRM, fitness app, and simple Google search) to figure the calories burned of my workouts and put that in MFP manually (Never went with the auto-generated calorie burn for the exercise I was logging).

As far as burning more calories when you were 'in worse shape'....you burn more calories if you are heavier and if your cardio/respiratory fitness isn't great. Once you get more into shape - yes your HR will not go as high (bc you've strengthened your cardo/respiratory fitness) and you will burn less calories (bc you aren't working as hard as you once were and you are smaller).

zebasschick

westrich20940 wrote: »

Yes, to all of this. I also used ~3 sources of info (Polar HRM, fitness app, and simple Google search) to figure the calories burned of my workouts and put that in MFP manually (Never went with the auto-generated calorie burn for the exercise I was logging).

As far as burning more calories when you were 'in worse shape'....you burn more calories if you are heavier and if your cardio/respiratory fitness isn't great. Once you get more into shape - yes your HR will not go as high (bc you've strengthened your cardo/respiratory fitness) and you will burn less calories (bc you aren't working as hard as you once were and you are smaller).

did your polar give you the lowest readings?:

kshama2001

Presumably if I had MapMyFitness synced to MFP, MFP would only give me the exercise calories, but looking at the number in the MMF app, I also get BEE calories. Until I figured this out, I was baffled by what seemed like freakishly high numbers.

I just enter exercise from the MFP database.

https://support.mapmyfitness.com/hc/en-us/articles/1500009117762-Why-Aren-t-My-Calories-Displaying-Correctly-

"... Our products calculate total burn, which includes caloric burn for both resting and active phases of activity. This means the calories you would typically burn by merely being alive automatically add to the number of calories you would burn from whichever activity you do."

westrich20940

zebasschick wrote: »

westrich20940 wrote: »

Yes, to all of this. I also used ~3 sources of info (Polar HRM, fitness app, and simple Google search) to figure the calories burned of my workouts and put that in MFP manually (Never went with the auto-generated calorie burn for the exercise I was logging).

As far as burning more calories when you were 'in worse shape'....you burn more calories if you are heavier and if your cardio/respiratory fitness isn't great. Once you get more into shape - yes your HR will not go as high (bc you've strengthened your cardo/respiratory fitness) and you will burn less calories (bc you aren't working as hard as you once were and you are smaller).

did your polar give you the lowest readings?:

@zebasschick - My Polar actually seemed fairly accurate when it was a lower intensity activity (walking briskly, hiking, or running at a slower consistent pace with not really much elevation change). Once the activity was more intense (running at a faster pace or a route that included elevation changes) it seemed to be an overestimate (sometimes by like 100 or more calories vs. the other sources of info I used). I would simply choose a calorie burn estimate that was a median number of all my data sources and put that into MFP. I lost weight as expected to seems it was more/less accurate in my case.

zebasschick

westrich20940 wrote: »

zebasschick - My Polar actually seemed fairly accurate when it was a lower intensity activity (walking briskly, hiking, or running at a slower consistent pace with not really much elevation change). Once the activity was more intense (running at a faster pace or a route that included elevation changes) it seemed to be an overestimate (sometimes by like 100 or more calories vs. the other sources of info I used). I would simply choose a calorie burn estimate that was a median number of all my data sources and put that into MFP. I lost weight as expected to seems it was more/less accurate in my case.

huh. my old polar - with or without polar beat - gives me a third to a half of the calories MFP and MMF gives me for exercise biking, treadmill and walking up and down stairs. all these get my heart up to a moderate rate.

AnnPT77

I always manually log exercises, but don't usually use MFP's calorie estimates. (I don't sync my Garmin because it's crazy far off for me on base calories.) I don't have high confidence in most of the exercise estimates sources for high accuracy, but this is how I estimate my exercise to get what I consider workable estimates:

* Machine rowing, noting that I usually do steady state pieces (not intervals) but vary the intensity from one workout to the next: Garmin machine rowing estimate. (I've compared it to Concept 2's weight-adjusted estimate; not enough difference to go through those minor extra calculations each time.) Also note that "steady state" is not a synonym for LISS: It can be MISS or HISS.

* On-water rowing: Garmin estimate, since RPE (rate of perceived exertion) is similar for workouts where Garmin gives me similar calorie calorie estimates.

* Walking: I use Garmin to get moving average speed and distance, then use the ExRx walk/run calculator with the energy box set on "net". (https://exrx.net/Calculators/WalkRunMETs)

* Strength training: I use MFP's estimate for "Strength training (weight lifting, weight training)". FWIW, it's close to the estimate that Garmin produces. IMU, some trackers now use METS to estimate strength training rather than including heart rate, not sure whether this is true for my device. (MFP uses METS.)

* Cycling: Garmin. I think this is the estimate in which I have the least confidence, but I'm not willing to invest in a power meter.

* Stationary bike: average watts X duration in hours X 3.6

* Things I do rarely: Any convenient semi-plausible number that's easy to obtain, because rare things don't matter much in the big picture.

That's just what I've settled on for my own use. It's worked OK for me for 8+ years now, but there's always a lot of sources of potential error in estimates, affecting all of daily life stuff, exercise, the statistics behind BMR/RMR estimates, and food logging. Constraining those potential error sources to a realm where no one thing distorts the total materially: That's my goal.

westrich20940

zebasschick wrote: »

westrich20940 wrote: »

zebasschick - My Polar actually seemed fairly accurate when it was a lower intensity activity (walking briskly, hiking, or running at a slower consistent pace with not really much elevation change). Once the activity was more intense (running at a faster pace or a route that included elevation changes) it seemed to be an overestimate (sometimes by like 100 or more calories vs. the other sources of info I used). I would simply choose a calorie burn estimate that was a median number of all my data sources and put that into MFP. I lost weight as expected to seems it was more/less accurate in my case.

huh. my old polar - with or without polar beat - gives me a third to a half of the calories MFP and MMF gives me for exercise biking, treadmill and walking up and down stairs. all these get my heart up to a moderate rate.

It was just a wristwatch/chest strap combo. Generally speaking, they aren't meant to be accurate for calories burned based on heartrate. The only reason I suspect it was accurate was bc of comparing it to the other sources of info I had, coupled with logging my calorie intake properly and - like I said, my rate of weight loss was exactly what I expected with all of those numbers. Weird how things are calibrated. I found my running app (RunKeeper) was usually the lowest estimate and now I don't bother with a HRM or any other sources...I just use that one to have an idea of 'about' what I burned and eat that, if I'm still hungry I simply eat more.

AnnPT77

westrich20940 wrote: »

Yes, to all of this. I also used ~3 sources of info (Polar HRM, fitness app, and simple Google search) to figure the calories burned of my workouts and put that in MFP manually (Never went with the auto-generated calorie burn for the exercise I was logging).

As far as burning more calories when you were 'in worse shape'....you burn more calories if you are heavier and if your cardio/respiratory fitness isn't great. Once you get more into shape - yes your HR will not go as high (bc you've strengthened your cardo/respiratory fitness) and you will burn less calories (bc you aren't working as hard as you once were and you are smaller).

Sure, body weight makes a difference for activities where we move our bodies through space. Body size isn't a meaningful contributor to the calorie burn for every exercise type, though.

Mostly, the calorie burn (for any activity) is coming from "the work" in the physics sense of work.

Feeling like you're not working as hard is irrelevant: That's pretty much the definition of improved fitness. For cardiovascular exercise specifically, as you get fitter, your stronger heart pumps more blood volume per beat, delivering more oxygen per beat, so your heart rate for the same exercise is lower (and it feels easier, of course). The oxygen consumption has a better correlation with calorie burn, but it's hard to measure oxygen consumption in the everyday context. Heart rate is just a somewhat-adequate proxy.

It's sort of true that people who're skilled at something become more efficient. The variation in efficiency between skilled and unskilled people is narrower or wider for different exercise types. In cycling, the efficiency variation is relatively small, for example.** If same-weight unfit and fit cyclists ride the same bike on the same course at constant weather conditions, and at the same pace/distance, their calorie expenditure will be very close.

(** See, for example: https://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=E292F3073D83BCB1DB240746DA23BE16?doi=10.1.1.469.3228&rep=rep1&type=pdf)

The (well accepted) cycling formula for calories based on watts doesn't include terms for efficiency or body weight. (Body weight may matter indirectly via power production/application, but it's not needed as an explicit term in the formula.)

Note that "less skilled" is not exactly synonymous with "less fit". Efficiency at an exercise is more often about the skill rather than the fitness. Believe me, I've seen very fit people be extremely unskilled (inefficient) rowers. They may have a little general physical-skills advantage over less fit people, but the key variable is still skill at the activity itself. (Even conditioning can be surprisingly sport-specific.)

I strongly suspect the popularity of "fit people burn fewer calories doing the same thing" is out of sync with the general truth of that assertion. In other words, I think the differences are not meaningfully big in a pretty wide range of cases. The personal experience of it feeling easier is persuasive, plus a lot of people think heart rate correlates directly with calorie burn, which is just not true. (That's leaving aside the fact that for many people, the heart rate estimates are relying on an age-based formula for maximum heart rate, and those estimates are inaccurate for a large minority of people, for reasons that have little to do with fitness.)

In at least some of the cases where efficiency matters, the less skilled person wastes motion that doesn't go into our routine ways of measuring the work, such as the measurement by an exercise machine. For me, watching a range of people at the gym using a Concept 2 rowing machine illustrates that pretty clearly: I see unskilled people wasting a lot of energy going for high strokes per minute (among other things), without the technique to accelerate the flywheel through that movement, so the pace/watts/calories seen by the machine are going to be lower than reality. (I don't have a clear idea how much lower, of course, but my guess would be that it could be meaningful: Some of those folks are doing something very intensely aerobic, even though the machine doesn't reflect that movement on its monitor.)

The METS-based process for estimating calories includes body weight explicitly (which is a plus or minus depending on the specific exercise). This approach is also well-accepted and research-based. Some METS values - IMO - lump too-varied things together, and some have been collected in ways that may not capture important variables. What's built into that method is assumption that for a well-specified activity (like running at a specific X miles per hour), relative efficiency between fit and unfit people of the same weight is not an important factor.

I know people here get worried that estimating exercise calories is pretty approximate, so one shouldn't risk it. The usual things that goes with that are that one should use a TDEE calculator (which averages in exercise without even knowing what the exercise is!), or not count exercise calories at all. (Zero is always wrong, but I guess there's a misperception that losing faster is better?).

I think there's also not a lot of appreciation for the range of variability inherent in estimating BMR/RMR, and the fact that the "activity factor" approach used by MFP and TDEE calculators is going to magnify the effect of that variation. It seems like many people mistrust exercise calories (generally a small-ish number in the big picture) and over-trust BMR/RMR + activity factor estimates (generally a big number in the big picture).

It's all estimates all over the place, and some of them are pretty approximate. It can still work.

yirara

I don't sync any devices because I know that the exercise calories my garmin records is often very off. It's individual of course, but for me walking gives about the same calories as running for the same distance. That's totally off. Thus at the moment I'm doing run/walk intervals to get back into running after a long pause, and the calories shown are pretty much what I'd expect when running the whole distance. Despite pulse going down very quickly when walking. So.. I use my best estimate instead of device data.

ythannah

I don't sync my Fitbit and manually log my exercise but I generally work on a TDEE method from my Fitbit's daily total, which seems to be pretty accurate for me. I am not trying to lose weight, however (currently need to gain). I'll deviate from the TDEE approach when I've had a high-exercise day like several hours of snow shovelling and logging that activity is a reminder that I should be getting extra calories that day.

westrich20940

AnnPT77 wrote: »

westrich20940 wrote: »

Yes, to all of this. I also used ~3 sources of info (Polar HRM, fitness app, and simple Google search) to figure the calories burned of my workouts and put that in MFP manually (Never went with the auto-generated calorie burn for the exercise I was logging).

As far as burning more calories when you were 'in worse shape'....you burn more calories if you are heavier and if your cardio/respiratory fitness isn't great. Once you get more into shape - yes your HR will not go as high (bc you've strengthened your cardo/respiratory fitness) and you will burn less calories (bc you aren't working as hard as you once were and you are smaller).

Sure, body weight makes a difference for activities where we move our bodies through space. Body size isn't a meaningful contributor to the calorie burn for every exercise type, though.

Mostly, the calorie burn (for any activity) is coming from "the work" in the physics sense of work.

Feeling like you're not working as hard is irrelevant: That's pretty much the definition of improved fitness. For cardiovascular exercise specifically, as you get fitter, your stronger heart pumps more blood volume per beat, delivering more oxygen per beat, so your heart rate for the same exercise is lower (and it feels easier, of course). The oxygen consumption has a better correlation with calorie burn, but it's hard to measure oxygen consumption in the everyday context. Heart rate is just a somewhat-adequate proxy.

It's sort of true that people who're skilled at something become more efficient. The variation in efficiency between skilled and unskilled people is narrower or wider for different exercise types. In cycling, the efficiency variation is relatively small, for example.** If same-weight unfit and fit cyclists ride the same bike on the same course at constant weather conditions, and at the same pace/distance, their calorie expenditure will be very close.

(** See, for example: https://citeseerx.ist.psu.edu/viewdoc/download;jsessionid=E292F3073D83BCB1DB240746DA23BE16?doi=10.1.1.469.3228&rep=rep1&type=pdf)

The (well accepted) cycling formula for calories based on watts doesn't include terms for efficiency or body weight. (Body weight may matter indirectly via power production/application, but it's not needed as an explicit term in the formula.)

Note that "less skilled" is not exactly synonymous with "less fit". Efficiency at an exercise is more often about the skill rather than the fitness. Believe me, I've seen very fit people be extremely unskilled (inefficient) rowers. They may have a little general physical-skills advantage over less fit people, but the key variable is still skill at the activity itself. (Even conditioning can be surprisingly sport-specific.)

I strongly suspect the popularity of "fit people burn fewer calories doing the same thing" is out of sync with the general truth of that assertion. In other words, I think the differences are not meaningfully big in a pretty wide range of cases. The personal experience of it feeling easier is persuasive, plus a lot of people think heart rate correlates directly with calorie burn, which is just not true. (That's leaving aside the fact that for many people, the heart rate estimates are relying on an age-based formula for maximum heart rate, and those estimates are inaccurate for a large minority of people, for reasons that have little to do with fitness.)

In at least some of the cases where efficiency matters, the less skilled person wastes motion that doesn't go into our routine ways of measuring the work, such as the measurement by an exercise machine. For me, watching a range of people at the gym using a Concept 2 rowing machine illustrates that pretty clearly: I see unskilled people wasting a lot of energy going for high strokes per minute (among other things), without the technique to accelerate the flywheel through that movement, so the pace/watts/calories seen by the machine are going to be lower than reality. (I don't have a clear idea how much lower, of course, but my guess would be that it could be meaningful: Some of those folks are doing something very intensely aerobic, even though the machine doesn't reflect that movement on its monitor.)

The METS-based process for estimating calories includes body weight explicitly (which is a plus or minus depending on the specific exercise). This approach is also well-accepted and research-based. Some METS values - IMO - lump too-varied things together, and some have been collected in ways that may not capture important variables. What's built into that method is assumption that for a well-specified activity (like running at a specific X miles per hour), relative efficiency between fit and unfit people of the same weight is not an important factor.

I know people here get worried that estimating exercise calories is pretty approximate, so one shouldn't risk it. The usual things that goes with that are that one should use a TDEE calculator (which averages in exercise without even knowing what the exercise is!), or not count exercise calories at all. (Zero is always wrong, but I guess there's a misperception that losing faster is better?).

I think there's also not a lot of appreciation for the range of variability inherent in estimating BMR/RMR, and the fact that the "activity factor" approach used by MFP and TDEE calculators is going to magnify the effect of that variation. It seems like many people mistrust exercise calories (generally a small-ish number in the big picture) and over-trust BMR/RMR + activity factor estimates (generally a big number in the big picture).

It's all estimates all over the place, and some of them are pretty approximate. It can still work.

Well this is a ton of excellent info!

I think it's hard for most to get their head around the reality that all of these numbers are estimates using estimates/averages to figure anyway. Many stress a lot (from my perspective) about what their activity level is...when you just need to pick one that seems to fit and do it and see if it's right. Even if choosing the right 'label' at first...it could still be too high or too low and the only way to know that is to do it and see what happens. People also seem to stress a lot about 'doing the wrong thing' for what is relatively a short amount of time - certainly not long enough to 'screw' anything up about their overall weight loss journey. That's just added unneeded stress IMO.