Net vs Consumed calories. still confused.

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Replies

  • tiwing
    tiwing Posts: 10 Member
    edited December 2020
    I normally try to estimate based on portion sizes and find a match in imperial measure in MFP ... I can visualize what 1/2 a cup or a cup is, but don't ask me what 100g looks like... I prob mess up the ones I only see in grams a bit. "food" for thought! I'll have to dig out the digital kitchen scale and see how bad I am at guestimating!
  • janejellyroll
    janejellyroll Posts: 25,763 Member
    tiwing wrote: »
    I normally try to estimate based on portion sizes and find a match in imperial measure in MFP ... I can visualize what 1/2 a cup or a cup is, but don't ask me what 100g looks like... I prob mess up the ones I only see in grams a bit. "food" for thought! I'll have to dig out the digital kitchen scale and see how bad I am at guestimating!

    If you're basing your calories in estimate on visual estimates, I wouldn't be surprised if you're actually eating more than you think you are. It's not that I think you're particularly bad at estimating, it's that multiple studies have proven that MOST of us are bad at this, at least when it comes to the degree of accuracy that is helpful for weight management.
  • lgfrie
    lgfrie Posts: 1,449 Member
    edited December 2020
    Wait, you've got a device telling you you're burning 800 calories a day with exercise (2400-1600)? It isn't impossible that that's a correct number, but thats a lottttttta exercise. At least two hours of VIGOROUS exercise. In all likelihood, the number is far lower.

    Almost all machines and apps provide comically high calorie estimates for exercise. Take a look at my machine's readout from today:

    81mfux6hdybn.jpg

    Nifty little workout summary, right? Notice anything funny about the numbers, though? This otherwise fine piece of gear thinks I burned 663 calories doing an hour of light cardio. LOL. So what really took place with my fat cells today? Here's the actual formula:

    3.6 * watts/hr = net calories burned.

    Or, in this case, 270.

    So I burned 270 net calories on a machine that tells me I burned 663. The machine's estimate is 2 1/2 times actual.

    So,beware devices that tell you you are burning 800 calories per day in exercise. It could easily be less than half of that.
  • tiwing
    tiwing Posts: 10 Member
    edited December 2020
    I appreciate all the feedback, - and yes now looking back at the past 7 days (where I can actually remember what I ate), I think I'm underestimating a lot. the main meals I think is OK. It's the snacking in between that I'm pretty sure is off. Yesterday I had a package of my guilty pleasure, peanut butter M&Ms. I had misread the package/portion and was way way under-representing what I ate. Plus I had a bowl of cheerios but instead of guessing it was one cup, I measured it. 1.5 cups. go figure. So time for a reset.

    As far as exercise, It seems like it might be a bit high, but not as crazy high as yours is reporting! I use garmin vivoactive watch .... Yesterday, for example, I was on the bike (indoor mag trainer) for 1h48m, avg 126 beats per minute, avg power 151 watts, reports 790 cal. Based on your calc, that would be 3.6*151*1.75hours = 950 watts. Wattage is reported on the mag trainer itself. It was a lighter ride that Saturday which was 2h10m average wattage 172w, avg HR 141 bpm. device shows 1144 cal. For reference my max HR is 180. Not tested mind you, but based on a maximum effort hill climb I hit 178 in the fall.

    Followed the ride on Sunday was a 45 min run avg 132 bpm for the entire run, but more in 150-155 for the 30 minutes I was actually running, 7.5km/h for the running portion but the trainer was sloped up a bit, reporting 450 cal. I'm typically an hour of exercise, mostly cardio, per day during the week, and up to 3-4 hours on the weekend days if the weather is good for a nice long ride outdoors.

    Really want to thank you all for your thoughts and feedback. It's opened my eyes a bit and caused me to rethink my approach. Like - cut back on the M&Ms :), and how to double check theoretical vs actual. If it's out of whack, something(s) are wrong and will make it easier to figure that out over time. Cheers!
  • heybales
    heybales Posts: 18,842 Member
    Ya, I was getting the sense for some of your workouts 800 was not out of question at all.

    I'll mention for the watts to calories conversion which is great to do, if you are to manually correct the workout info in Connect, add back the BMR calories for that chunk of time, since you have a healthy chunk of time, hour is probably 80 cal abouts.

    Because on Garmin's side and reporting - they take it back out anyway. So you'd be using a very accurate number and then incorrectly having BMR removed by Garmin.

    As to what comes over to MFP it makes it correct too - since GC sends the daily burn and the workouts both.
    Especially now that it sounds like you'll be tightening up your food logging.

    Hmmm, cut back on M&M's, especially the peanut butter? or find a way to make them fit! Oh yes.
  • tiwing
    tiwing Posts: 10 Member
    Wanted to circle back on this and say thanks to all those who commented and helped. I went back through all my numbers and (assuming Garmin Vivoactive is "correct" for exercise calories), I was under-estimating my food by a whopping 25%. So I worked an "adjustment factor" into my spreadsheet and for Dec and Jan so far it seems to be working out. I guess a combination of the sauces and portions being a little larger than I thought make a lot of difference!

    Anyhow, thank you.

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