Where is the greatest inaccuracy?
garystrickland357
Posts: 598 Member
I'm curious what opinion is of experienced folks here. Most folks here seem to combine logging their food and exercising when they begin a weight loss journey. I know that's a sweeping generalization but i think it is often true.
Often when someone isn't losing as expected the focus tends to be on their diet (in terms of Calories In). There is a lot of discussion about logging accuracy and honesty in logging - and rightfully so. My concern though is that there are also errors in the number of calories burned during exercise. These discussion do happen but it seems with less frequency. In any case, my question is which is generally more inaccurate - the calories consumed or the calories burned during exercise?
As I look at my last several weeks of maintenance I see that I average ending the day with a 350-400 calorie deficit - but I'm not losing weight. That means I'm not really experiencing a deficit. If I split the deficit it would not be hard to be to be off by 175 calories a day in logging and 175 calories in exercise. I'm not sure though it's an even split and I have no idea which error is the greatest.
At the end of the day I'm not sure it matters but it seems like an interesting topic to discuss.
Often when someone isn't losing as expected the focus tends to be on their diet (in terms of Calories In). There is a lot of discussion about logging accuracy and honesty in logging - and rightfully so. My concern though is that there are also errors in the number of calories burned during exercise. These discussion do happen but it seems with less frequency. In any case, my question is which is generally more inaccurate - the calories consumed or the calories burned during exercise?
As I look at my last several weeks of maintenance I see that I average ending the day with a 350-400 calorie deficit - but I'm not losing weight. That means I'm not really experiencing a deficit. If I split the deficit it would not be hard to be to be off by 175 calories a day in logging and 175 calories in exercise. I'm not sure though it's an even split and I have no idea which error is the greatest.
At the end of the day I'm not sure it matters but it seems like an interesting topic to discuss.
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Replies
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I look at it from 2 angles...
- Food intake accounts for far more calories than does exercise. So a minor improvement in overall accuracy has a far greater impact.
- It is far easier (in most cases) to make improvements in accuracy measuring/logging food than it is exercise.
Either of those things alone makes me feel that paying closer attention to the accuracy with which you measure/log food is going to pay better dividends than paying extra attention to exercise cals. As you said, we are speaking generally here, but that's my take on it.
As for where the larger/greater inaccuracy lies... I think it depends on the person. Most newbies are probably going to see greater inaccuracies in their food estimates as most new people don't come here with a good sense of potion sizes based on weight/measure, but rather packaging, supersizing, relative to plate/bowls, etc.12 -
I think estimating calories out is more difficult in regards to accuracy. That said, I think a lot of people, especially new people just take whatever from the database whether that's food or exercise and just log it without verifying or questioning the validity of a food entry or their energy expenditure from a given exercise.
I don't think it comes up as much because I'd wager there are more users of MFP who don't use MFP properly and don't understand eating back calories than their are people who understand what is going on here and how this tool works.
I personally didn't really have a problem with either. It was easy enough to verify my food from the database, and I primarily used my HRM less my basal calories to estimate my calorie expenditure for cardio and I just used the database entry for strength training to get those calories.7 -
I also think it depends on the person. I've been weighing and logging for years so I would say that I personally would have the biggest inaccuracies with my exercise calories. Plus I often burn more than 1,000 calories either hiking, backpacking or snowshoeing in the mountains so I find vast differences in the various exercise calculators.2
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For me, personally, I'm sure it's food. I'll give you some examples but as @jjpptt2 says, the math makes it so food has to the biggest contributor.
I get about 2,400 calories per day to lose a small amount of weight slowly. I love cycling, and have the ability to measure boner calories with great accuracy. I mostly only ride when it's dry out, an for anywhere from 30 minutes to 2 hours in a typical day. That's 200 to 1,200 calories. Because of weather and other obligations, I can't ride 2 hours every day. Even on days I can, that adds half my normal calories. Most days, just being alive dwarfs my exercise calorie burn.
On the other hand, I don't measure or log the oils I use to cook. That's a pretty obvious mistake, I may be forced to change this one day. Some days this might add a couple hundred unaccounted for calories. I don't have the ability to measure my skiing calories with much accuracy, but something like a lot of oil probably comes to more than the error guessing exercise calories.
Last thought: most trackers and apps overestimate exercise calories. Like vanity sizing. I just burned 3,000 calories walking across the parking lot. On the other hand, most people underestimate their food calories, either by portion size, or by forgetting a snack. So it's not either or, it's a 1, 2 punch.
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NorthCascades wrote: »For me, personally, I'm sure it's food. I'll give you some examples but as @jjpptt2 says, the math makes it so food has to the biggest contributor.
I get about 2,400 calories per day to lose a small amount of weight slowly. I love cycling, and have the ability to measure boner calories with great accuracy. I mostly only ride when it's dry out, an for anywhere from 30 minutes to 2 hours in a typical day. That's 200 to 1,200 calories. Because of weather and other obligations, I can't ride 2 hours every day. Even on days I can, that adds half my normal calories. Most days, just being alive dwarfs my exercise calorie burn.
On the other hand, I don't measure or log the oils I use to cook. That's a pretty obvious mistake, I may be forced to change this one day. Some days this might add a couple hundred unaccounted for calories. I don't have the ability to measure my skiing calories with much accuracy, but something like a lot of oil probably comes to more than the error guessing exercise calories.
Last thought: most trackers and apps overestimate exercise calories. Like vanity sizing. I just burned 3,000 calories walking across the parking lot. On the other hand, most people underestimate their food calories, either by portion size, or by forgetting a snack. So it's not either or, it's a 1, 2 punch.
lol - that's pretty much my opinion - the 1,2 punch...
I just probably don't know my cycling calories to the degree of accuracy you know yours. I feel like they are pretty close. I log a lot like you too - I log calorie dense things and ignore some others. It works for me - I lost 75 pounds and I'm currently maintaining - BUT - I also know I'm off every day.
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I believe exercise estimates get far too much of the blame for when a person's results don't match expectations.
For the vast majority of people with relative low to "normal" levels of exercise then the deviation would have to be massive for it be as significant as many people seem to believe.
Some of the MFP database entries and some apps and some machines give pretty poor estimates but for most people not enough to account for the frequent posts "I'm doing everything right but not losing weight". A few hundred over estimated calories a few times a week does not equal 3500 calories a week.
There's also some psychology at play - a combination of a strange guilt around exercise calories (regarding them as a bonus) and the common and understandable desire not to have to eat less.7 -
That is why in maintenance I prefer using a TDEE calculator with rolling 12 week data. I log and weigh to keep up.0
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I think it comes down to if you are as accurate as possible with logging your base calories, or your way of logging is giving you your expected deficit without exercise, you can use your own data to get a good estimate (or device comparison) of your exercise cals. (It doesn’t work in reverse.
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I had a small calorie allowance (I am small) so accuracy in food logging was the first thing I needed.
Once I had that, I could use my data to get a good estimate of cals burned per hr in the class I was doing 3x a week and compare it against the cals MFP was giving me to achieve my desired loss per week. It turned out to be within 20-30 cals so I rounded it out.
The exceptions were-
When I did Zumba, MFP gave me 200 cals over my burn, but I soon found that because I had good personal data.
The other was when I started lifting and took the, old, general advice that the cal burn wasn’t worth logging. For someone my size with a small cal allowance, those cals were needed. I was in maintenance and losing fast. Error soon found.
So from personal experience over the years, I look at food logging, then where the calorie burn estimate from exercise is coming from. Unless it is something incredibly obvious like 600cals for 28 min of 30 Day Shred.
Cheers, h.3 -
I think the hard answer is that everyone will work their way into a status quo with the equipment, dedication and skills they have at their disposal. Whether something ends up mathemetically correct and making sense every day is sort of irrelevant if you're getting where you're going and staying sane along the way. This is why, e.g. someone may do fine using machine generated cardio calorie burns when for 9/10 people they are over-estimated. Somewhere else in their set-up, it's being compensated for in a way that they are able to work with. Someone else may underestimate their food intake by using cups and pre-made database entries but not count their exercise cals out of some mistaken comprehension. There are as many ways to get it right as there are personalities and preferences here.1
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I'm glad you brought this topic up. I have a neighbor who is friends with me on Myfitnesspal and I can see that she is struggling to lose weight. I looked into her food diary, since it was not locked and right away I could tell that she is completely over estimating the amount of calories burned running. She probably weighs around 200lbs and logs 1 hour of running at almost 1,000 calories burned. First of all, I know she is not running for an entire hour. Second of all, she is doing more like light jogging than running. Since she feels so good about the amount of calories burned, it probably justifies what she then eats during the day. I don't usually eat the calories I burn but it looks like she does. I so want to help her but don't have a clue how to. I have lost 20 lbs this year (from 5'4" 160 lbs) and at first I thought her seeing my weight loss would inspire her, but now I think the opposite is happening.
Anyway, thanks for posting this discussion, I think it is important for people to not over estimate calories burned.4 -
It's the sort of thing I find best to not preach to them about. They'll find out in time. I had a discussion with a guy at a very similar weight to me. I'm down 35lbs since June and he's down 11.
He swears by some app he uses and eats back his exercise calories. He showed me a 4 mile walk over 80 minutes which he said burnt 680 calories. He then ate them back on top of his 2100 allowance. Then wonders why he's not losing and laughs at me when I log a 90 minute walk as 150 calories as that's what I allow myself to eat back.
As I say they'll learn some day. Maybe.1 -
I think like @jjpptt2 said, intake is a much larger contribution to the calculation than exercise is - and that’s even true for someone like me with a 1200 calorie base to lose less than a pound a week while training for a marathon (everyone simmer down-I eat all my exercise calories).
I also think consistency plays as great or greater role than accuracy. People tend to do the same exercises (or same types) fairly consistently. Databases, trackers, online calculators, etc tend to be within ~10% of each other and people are likely to stick with one particular method. So from an exercise standpoint-the calories out side is likely to be consistent-even if not accurate.
One can make adjustments and work with consistent data.
Food intake tends to vary (unless you’re a robot who eats exactly the same thing in exactly the same quantities all the time). Logging errors and/or omissions are likely - even for the most seasoned, careful logger. Additionally, I do believe we all reach a limit of what is feasible for us to do in terms of food logging detail (do we REALLY weigh every lettuce leaf in every salad?) while maintaining sanity (and a normal social life).
Food is inconsistent.
Most of us have systems that work fairly well-we know maybe we don’t weigh/log x, but we also don’t count y for activity and know it’s probably a wash at the end of the day. Because we have limits in terms of our desire to weigh seasonings for a sauce.
For someone having issues where they aren’t losing as expected-the food is more likely to be a moveable metric - in terms of improving consistency.
It’s less important that I’m logging specifically, lab accurate 1200 net calories every day. Its more important that whatever I’m logging (in and out) is consistent as I can then adjust as needed.
At least that’s my take.
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Depends on the person, but it really does not matter. If results are off, adjust. If you think you burn 2200 and you seem to get results that suggest you only burn 2000, you can just eat less or exercise more (and if the real issue is the logging, as long as you continue being consistent it should still fix the problem).5
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No question in my mind that it's eating inaccuracy.
The way I see it:
Person A has a calorie target of 2000 calories per day so 14,000 per week. They also exercise 3 days a week and burn 500 calories per session so 1500 calories per week. (I tried to pick pretty middle ground general figures)
If Person A's logging is negatively inaccurate by 20% this means means they're eating an additional 2,800 calories per week and burning 300 calories less than expected. Fixing any exercise inaccuracies will have a pretty minimal impact whereas addressing the calorie intake will be far more significant.
Next I think it's easier to accurately control the measurement calorie intake. Ask a group of people how long they exercised for and about how hard they'll all be able to give you a rough estimate of RPE and amount of time they spent but they're all just guesses really. Get someone to weigh and measure their food and they can get far more precise with their measurements.3 -
There is a reason the saying you cant out exercise your fork exists.3
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Either could be off, but I think you left out an important variable, or maybe two variables: (1) The variation in the part of CO between BMR/RMR and total NEAT (i.e., daily activity), and possibly (2) additional variation between the population mean and N=1 on various aspects of this.
As far as #1:
For most people (not all), on the CO side, the biggest chunk of TDEE is BMR/RMR. Next biggest is daily activity (NEAT excluding BMR/RMR). For most people (again, not all), intentional exercise numerically trails both of those. There are potentially large variations in daily activity between people, from household habits to jobs to simple twitchiness. (Fitness trackers try to capture some of this, but do it very imperfectly.) The potential for estimating error in this area is very large.
With respect to #2:
Observation of conversations here, and a general understanding of statistics besides, suggests that any given n=1 TDEE or NEAT likely varies a bit from the demographically-similar population mean, and by different amounts for each n. How much? Dunno. I think "science" has some glimmerings of how much, but doesn't really know either . . . and doesn't have a super-great handle on exactly why they differ, either.
People waffle about how tiny factors like TEF contribute, or variations in thyroid functioning, or the behavior of our gut microbiome (in harvesting & making available, or sequestering from us, the nutrients/calories in our food), and more. They're tiny factors, for sure. What do they add up to, if all the factors line up in the happy "can eat more calories and lose" direction, vs. the unhappy "gain on fewer calories" direction. Dunno. Do they ever align in that way? Often? Dunno.
As far as the two you name, I think the practical/actual variation between people is much greater than the theoretical variation that comes from unavoidable estimating error (i.e., the latter if everything were done as accurately as practical with common tools). I see people logging "lasagna 4in. square" or even "lasagna 1 serving" (maybe own recipe, maybe not), and others logging "tomato sauce 58g, lasagna pasta 47h, onions 22g (etc.)". Different.
I see people understanding, or not understanding, that different estimating methodologies might be more accurate for different types of exercise . . . or not understanding that. Some might pick the higher of (for example) HRM vs. exercise machine (bonus!!), some might pick the lower (caution). Various people discount by various percentages for various reasons, good and bad.
Heck, I see people saying "eating maintenance calories but still losing (gaining) weight" - heaven knows what else they may be thinking/doing! The individual variation in understanding of the process, and in actual practice of the process, is almost certainly greater than the error inherent in "as accurate as reasonably practical" logging.
I think what you asked is a completely unanswerable question.
But I also think it doesn't matter much, because I'm a great believer in the power of "be consistent, monitor, adjust".
(PDCA, for the old school among us.
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My experience suggests that my log of calories in might be 5-10% off (from time to time), whereas my calories out (Fitbit) figure is commonly inaccurate by a much bigger margin. I generally have to leave at least half my exercise calories “in the bank” on exercise days or I gain weight (averaging over the week).
Over the last month, Fitbit says I’ve been burning a daily average of about 2,700 cals, whilst eating an average of about 2,250 a day. My weight trend is flat.0 -
There can be errors both with calories in and exercise cals, none of them can be calculated with certainty - that's why it takes time to figure out maintenance calories and even then its just approximate. Personally I only loosely count calories now, I regularly exercise but roughly know how many calories I can maintain on. I try to generally not overthink the process any more. Having a weight range helps.4
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I note many medical professionals recommend that people first implement a caloric deficit and then begin an exercise routine. The rationale behind this is that most will eat more and feel that this is justified due to them working out.
The evidence suggests it's likely an issue with Caloric Intake (CI) miscalculations over Caloric Output (CO). Considering scale of magnitude CI compared to BMR and exercise related CO there is a highest chance of error within CI simply due to the average CI being somewhere ~1500 kcals/day whereas the average CO (other than BMR) is ~300 kcals/day. In nearly all cases there is inherent inaccuracies in both, but CI carries the highest degree of risk.
While it may seem trite this is why the first response to the question "Why am I not losing?" is "Look to your logging."4 -
I mark as sedentary, because I'm not doing much with exercise. First I am doing a caloric reduction, and then I will ultimately add the exercise back but only some light swimming at first. I'm not planning on doing much gym work until March. I have had over 1 month of calorie reduction thus - averaging about 9000 a week, and a 9 lb weight loss. Once I reach a phase 1 goal weight of phase 1 (which will probably take me 3 more months), I plan to do maintenance, and exercise - possibly bring up 200 more calories a day and add more regular light exercise. I think that we do all burn calories differently - so I will see where that takes me after a couple of weeks. Because, yes, the more you exercise, you typically can't eat as low a calorie amount as 1200 a day - which I am doing fairly well.1
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I think what you asked is a completely unanswerable question.
I'm good at asking those, lol.
I appreciate the discussion. As I said I'm managing to maintain my weight weight - which means I'm in a CICO balance, but my logging shows me at a daily deficit. I understand that on the one hand that is irrelevant because I am achieving the outcome I desire. It's more of an intellectual exercise for me wondering where my sources of error are in my logging/exercise balance.
I think I'll just keep truckin' and not worry about it.
Thanks again all...4 -
garystrickland357 wrote: »
I think what you asked is a completely unanswerable question.
I'm good at asking those, lol.
I appreciate the discussion. As I said I'm managing to maintain my weight weight - which means I'm in a CICO balance, but my logging shows me at a daily deficit. I understand that on the one hand that is irrelevant because I am achieving the outcome I desire. It's more of an intellectual exercise for me wondering where my sources of error are in my logging/exercise balance.
I think I'll just keep truckin' and not worry about it.
Thanks again all...
To what are you comparing your logged data that makes you say you're at a deficit: MFP estimate? Fitness tracker? TDEE calculator? Past personal experience data?
Pretty much nothing but past personal data has ever given me a usefully accurate maintenance estimate, and even that changes seasonally, somewhat.5 -
garystrickland357 wrote: »I'm curious what opinion is of experienced folks here. Most folks here seem to combine logging their food and exercising when they begin a weight loss journey. I know that's a sweeping generalization but i think it is often true.
Often when someone isn't losing as expected the focus tends to be on their diet (in terms of Calories In). There is a lot of discussion about logging accuracy and honesty in logging - and rightfully so. My concern though is that there are also errors in the number of calories burned during exercise. These discussion do happen but it seems with less frequency. In any case, my question is which is generally more inaccurate - the calories consumed or the calories burned during exercise?
As I look at my last several weeks of maintenance I see that I average ending the day with a 350-400 calorie deficit - but I'm not losing weight. That means I'm not really experiencing a deficit. If I split the deficit it would not be hard to be to be off by 175 calories a day in logging and 175 calories in exercise. I'm not sure though it's an even split and I have no idea which error is the greatest.
At the end of the day I'm not sure it matters but it seems like an interesting topic to discuss.
Measurement accuracy or contribution to outcomes?
It's much easier to have a high degree of accuracy around input, but error and that measure has a greater effect on outcomes. It's difficult to get a consistent, accurate, measure of energy of, but equally the size of error is likely to be less as exercise is such a lower component of the whole.
That's no different to what several others are saying, but clearly it's a good source of discussion around here.0 -
garystrickland357 wrote: »
I think what you asked is a completely unanswerable question.
I'm good at asking those, lol.
I appreciate the discussion. As I said I'm managing to maintain my weight weight - which means I'm in a CICO balance, but my logging shows me at a daily deficit. I understand that on the one hand that is irrelevant because I am achieving the outcome I desire. It's more of an intellectual exercise for me wondering where my sources of error are in my logging/exercise balance.
I think I'll just keep truckin' and not worry about it.
Thanks again all...
To what are you comparing your logged data that makes you say you're at a deficit: MFP estimate? Fitness tracker? TDEE calculator? Past personal experience data?
Pretty much nothing but past personal data has ever given me a usefully accurate maintenance estimate, and even that changes seasonally, somewhat.
Yes. I'm using the MFP estimate. I try to log food accurately and I synch with my Garmin for the exercise calories. I'm just going of those numbers that tell me I still have calories remaining at the end of the day. I"m not hungry and I am maintaining so that's how I know I'm not actually in a deficit. I know my personal data and trend on the scale are what I need to watch. I was just curious where the source of the discrepancy was most likely.
And related to your comment - I thought the MFP calorie suggestion WAS a TDEE calculator. I answer the same questions for MFP as I do in an online TDEE calculator. What's the difference?0 -
My underlying thinking in this thread is how to possibly change any setting I have in my Garmin or MFP to make the estimates more accurate for me. I would like to use these tools for maintenance over time. I see some folks here logging for years. It would make sense to me to optimize this tool for me individually. It works for me to know there is a "fudge factor". I know that If I eat back about 1/2 my exercise calories that everything works out. I'd just feel better if I could eliminate the "fudge factor".2
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garystrickland357 wrote: »My underlying thinking in this thread is how to possibly change any setting I have in my Garmin or MFP to make the estimates more accurate for me. I would like to use these tools for maintenance over time. I see some folks here logging for years. It would make sense to me to optimize this tool for me individually. It works for me to know there is a "fudge factor". I know that If I eat back about 1/2 my exercise calories that everything works out. I'd just feel better if I could eliminate the "fudge factor".
First you need to understand where your inaccuracies are. That's specific to you and may or may not be in line with what most of us do/think/see. Then you can make adjustments as needed.
If you know with reasonable certainty that eating back half your calories makes things line up as they should, then that's your fudge factor - 50% of your burn estimates. Make that adjustment and you're set, right? Or am I missing something?1 -
With online TDEE calculators your exercise is included.
With MFP’s NEAT calculator no exercise is included, just daily activity.
If your confident your food logging is accurate, within personal idiosyncrasies, (ie l didn’t weigh my morning mandarin, it was always 45cals.) it is down to your 50% exercise cals.
If you are consistent with what exercises you do, workout (from your device minus 50%) your calorie burn per minute for each exercise then enter that in MFP ‘cardio’ as a personal exercise.
Very hypothetical example-
ie: ‘my hikes’ 60min 240cals (4cals a min).
Now, every time you do a hike it will scale your burn to the time taken. I think it also takes your weight into account but not sure as I have been weight stable for so long.
The advantage of this is it is device independent so if you change your device you still know what your cal burn for exercise is.
Start a new exercise? Monitor it on your device, do the math, make it a personal MFP exercise entry.
Can you tell I’m a personal data person and not a device person?
Cheers, h.
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Is your Garmin linked as an activity tracker? So you’re getting your workouts synced but also a line for a “steps” adjysment?
If so, you can do some fiddling with your mfp settings to get a little closer to “correct” but it’s not really any easier than just eating 50% of your exercise calories.
You can reduce the amount of your “steps” adjustment my increasing your activity level setting in mfp. The “steps” adjustment is the difference between what Garmin says you burned and what mfp thinks you burned (NEAT + workouts). If you raise your activity setting on mfp, mfp will think you’re burning more (Higher NEAT) and your “steps” adjustments will be lower (as your Garmin will record the same number but mfp will think you burned more and the resulting difference/adjustment line will be smaller)
This also raises your calorie goal so you’d need to lower that too.
So...you can adjust it but it’s not really easier than just eating 50% of your exercise calories.
I think the basic message on this thread is that ultimately, the only thing that really matters is what is actually happening. And if you have a consistent way to achieve that-carry on.1 -
garystrickland357 wrote: »garystrickland357 wrote: »
I think what you asked is a completely unanswerable question.
I'm good at asking those, lol.
I appreciate the discussion. As I said I'm managing to maintain my weight weight - which means I'm in a CICO balance, but my logging shows me at a daily deficit. I understand that on the one hand that is irrelevant because I am achieving the outcome I desire. It's more of an intellectual exercise for me wondering where my sources of error are in my logging/exercise balance.
I think I'll just keep truckin' and not worry about it.
Thanks again all...
To what are you comparing your logged data that makes you say you're at a deficit: MFP estimate? Fitness tracker? TDEE calculator? Past personal experience data?
Pretty much nothing but past personal data has ever given me a usefully accurate maintenance estimate, and even that changes seasonally, somewhat.
Yes. I'm using the MFP estimate. I try to log food accurately and I synch with my Garmin for the exercise calories. I'm just going of those numbers that tell me I still have calories remaining at the end of the day. I"m not hungry and I am maintaining so that's how I know I'm not actually in a deficit. I know my personal data and trend on the scale are what I need to watch. I was just curious where the source of the discrepancy was most likely.
And related to your comment - I thought the MFP calorie suggestion WAS a TDEE calculator. I answer the same questions for MFP as I do in an online TDEE calculator. What's the difference?
The MFP calculator is a NEAT calculator: It asks the same questions as most TDEE calculators, but - reading the instructions carefully - the activity setting is based on job/daily life, and doesn't include intentional exercise, which (of course) is why you estimate your intentional exercise separately, log it, and eat back those calories, too (or some of them, if you're worried that they may be overestimated).
The non-MFP TDEE calculator instructions commonly say that your activity level setting includes your intentional exercise: The descriptors commonly include things like "Slightly Active, Exercise or Light Sports 1 to 3 Days a Week, Light Jogging or Walking 3 to 4 Days a Week" (that one's from Sailrabbit, if it matters). So, that calorie estimate already includes your expected exercise, just assumed to always happen consistently, and averaged over both active and inactive days.
Behind the scenes, both MFP's calculator and the TDEE calculators make an estimate of your BMR/RMR based on research studies (they guess the mean, I believe, considering your personal details like age, weight, etc.). There are several different common research-based methodologies for estimating BMR/RMR (Harris-Benedict, Mifflin St Jeor, Katch-McArdle, etc.). The aforementioned Sailrabbit shows several; for me, the difference between smallest & largest is 84 calories.
Then, either type of calculator uses a multiplier, selected based on your activity level. Different calculators will use different multipliers, with obvious reasons for NEAT multipliers differeing from TDEE multipliers, and the potential for different calculators to have more/fewer activity levels, so need more/fewer different multipliers.
So, if your experience differs from the calculator, it could be because:
* Your BMR/RMR varies from the population-based estimate (range of adult RMR/BMR is fairly narrow, I think, so maybe not a huge contributor . . . but it later gets multiplied by the activity factor, remember).
* Activity factors are very, very general. They don't account for much of the diversity of human behavior. There are only 4-6 or so different levels of activity among all humans? That's a little approximate, even if we interpreted the instructions in exactly the right way. Because the activity factor translates to a multiplier, it will increase the numerical calorie impact of a variation from the norms in BMR/RMR.
* Your exercise is mis-estimated, or your intake is mis-estimated, without any particular judgement about whether that mis-estimate is due to sloppiness/forgetfulness/other human failing, or unavoidable "one apple sweeter than the next" stuff.
. . . and I'm probably forgetting some.
Bottom line: I think you have to be really, really, really average in order for these things to work out exactly. It's estimates and research-study-population means all the way down, and some pretty rough estimating methods at that, regardless of how science-based. Experience is the real deal, even with sloppy logging, especially if the sloppiness is reasonably consistent.
Personally, I just did a bunch of data analysis various ways when I was approaching maintenance, and used my own data to roughly estimate my NEAT. Since I (by choice) slightly undereat it most of the time in order to significantly overeat it once in a while, I manually set MFP to the number of calories I want to eat most days. (Its "In 5 weeks" thing still makes me laugh, because that seems to use profile settings, where I'm set at "active" even though I'm high-sedentary to low-slightly-active in terms of steps, and it still thinks I'll gain on my daily small-deficit calories. ). Then I include some scale-watching (daily weigh-ins, Libra) to keep things in check because my NEAT estimate was rough (I think +/- 200 or so, so around 10%).garystrickland357 wrote: »My underlying thinking in this thread is how to possibly change any setting I have in my Garmin or MFP to make the estimates more accurate for me. I would like to use these tools for maintenance over time. I see some folks here logging for years. It would make sense to me to optimize this tool for me individually. It works for me to know there is a "fudge factor". I know that If I eat back about 1/2 my exercise calories that everything works out. I'd just feel better if I could eliminate the "fudge factor".
If your Garmin knows your current details, and especially if you can give it your actual HRmax, stride length, etc., that's probably about the best you can do on that side. Doing its little self-tests (VO2max or whatever) theoretically could improve things, too, but I'm not sure whether/how much they use those in calorie estimates). eta: I use the MFP database estimate for strength training, on the rare occasions when I buckle down and do some.
My Garmin, in terms of all-day TDEE calories, seems to underestimate by about the same amount as MFP, FWIW.
I suppose I could figure out the approximate average error percent, sync the Garmin to MFP, and adjust by the average error percent daily, but the Garmin came into my life just a few months ago, so that seems like too much hassle at this point. I used to use Polar exercise calorie estimates for cardio (even for cardio it doesn't estimate all that well, like intervals), so now I just log Garmin exercise activity calories in the same way I used to log Polar's (they seemingly differ, by the way, for more or less equal activity intensities, but not enough to get me worried about the impact on my day/week.
If you want to eliminate the fudge factor, maybe change your base calorie goal to a number you know is sensible, and either look at the calorie goal as a TDEE (if you like eating the same amount every day, or weekly variations on that theme), or as NEAT (if your exercise varies more randomly) then still log exercise. I do the latter, since much of my exercise for much of the year is weather-dependent, and my intentional variation on the intake side is enough complication for me.
Sorry about writing a book, especially since you probably didn't need all of it. 3 -
garystrickland357 wrote: »My underlying thinking in this thread is how to possibly change any setting I have in my Garmin or MFP to make the estimates more accurate for me. I would like to use these tools for maintenance over time. I see some folks here logging for years. It would make sense to me to optimize this tool for me individually. It works for me to know there is a "fudge factor". I know that If I eat back about 1/2 my exercise calories that everything works out. I'd just feel better if I could eliminate the "fudge factor".
Is it only purposeful exercise estimates that Garmin is sending over or is it steps/activity etc.. too?
The discrepancy could be from one or the other or both.
What types of exercises?
Personal experience with my cycling specific Garmin is that it under estimates my outdoor cycling and especially significantly underestimates on low intensity rides. I've not found a way to correct that without messing up other aspects of its data that are useful to me.
(Unfortunately Strava now takes those estimates rather than its own which were generally better for me.)
The exception is when Garmin is fed power meter data when it uses the commonly accepted formula for the conversion of watts to calories and I'm happy to accept that as accurate.
Personally I'm against using fudging one side of the calorie balance to compensate for inaccuracies elsewhere as that falls apart when your routine changes. For example my cycling volume has more than doubled in a few years from 2,400 miles to 5,500.
Injury or lack of time to exercise would also mess things up whereas an at least reasonable estimate for both sides of the equation would still work.3
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