Where is the greatest inaccuracy?

Options
garystrickland357
garystrickland357 Posts: 598 Member
edited December 2018 in Health and Weight Loss
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.
«13

Replies

  • lalalacroix
    lalalacroix Posts: 834 Member
    Options
    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.
  • garystrickland357
    garystrickland357 Posts: 598 Member
    Options
    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. :neutral:

    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.
  • SummerSkier
    SummerSkier Posts: 4,788 Member
    Options
    That is why in maintenance I prefer using a TDEE calculator with rolling 12 week data. I log and weigh to keep up.
  • middlehaitch
    middlehaitch Posts: 8,483 Member
    Options
    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. :) )

    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.
  • MelanieCN77
    MelanieCN77 Posts: 4,047 Member
    Options
    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.
  • trishklein
    trishklein Posts: 14 Member
    Options
    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.
  • RoyBeck
    RoyBeck Posts: 947 Member
    Options
    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.
  • Duck_Puddle
    Duck_Puddle Posts: 3,224 Member
    Options
    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.


  • Danp
    Danp Posts: 1,561 Member
    edited December 2018
    Options
    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.
  • Poisonedpawn78
    Poisonedpawn78 Posts: 1,145 Member
    Options
    There is a reason the saying you cant out exercise your fork exists.
  • AnnPT77
    AnnPT77 Posts: 32,070 Member
    Options
    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. ;) )
  • Johnd2000
    Johnd2000 Posts: 198 Member
    Options
    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.
  • LivingtheLeanDream
    LivingtheLeanDream Posts: 13,345 Member
    edited December 2018
    Options
    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.
  • CSARdiver
    CSARdiver Posts: 6,252 Member
    edited December 2018
    Options
    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."
  • IsETHome
    IsETHome Posts: 386 Member
    Options
    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.

Categories