Where is the greatest inaccuracy?

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.

That is why in maintenance I prefer using a TDEE calculator with rolling 12 week data. I log and weigh to keep up.

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.

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.

There is a reason the saying you cant out exercise your fork exists.

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.

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."

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.

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.

garystrickland357 wrote: »

AnnPT77 wrote: »

garystrickland357 wrote: »

AnnPT77 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.