How do you know how many calories you're really burning?

cncrafton
cncrafton Posts: 82 Member
in Fitness and Exercise
Is there any way to really tell how much you're burning aside from wearing a device? When I do the elliptical, the machine says I burn about 100 calories in 30 minutes, and I've heard that the machines often overestimate. But MFP says I've burned about 581, and a few other calculators are giving me similarly high numbers. I guess I'm not working out that hard - I probably average about 55 rpm during 30 minutes.

I'm afraid of entering too many calories burned, but I'm also concerned about burning a lot and not accounting for them and then not really eating enough. is there any sort of fairly reliable formula?

Thanks!

Replies

  • YoungDoc2B
    YoungDoc2B Posts: 1,593 Member
    100 calories in 30 minutes? That definitely doesn't sound right unless you're going at a snails pace. How about you just average the machine+mfp's numbers?
  • Kaydoggie
    Kaydoggie Posts: 98 Member
    Get a good Heart Rate Monitor :) I don't excersize without one!! Its the most accurate guage to calories burnt.
  • neverstray
    neverstray Posts: 3,845 Member
    There's really no way to now. An HRM is only measuring your heart rate, it really has no idea how many calories you are burning. But, given what you have, an HRM is probably the best tool. Although, despite what everyone says, I find MFP to be fairly accurate.
  • MyaPapaya75
    MyaPapaya75 Posts: 3,143 Member
    Heart Rate Monitor I never just go by machines or anything else..I use a Polar///MFP tends to be pretty accurate for those fairly within their target weight range but if you are obese I would take off 100 to 150 cals per any workout
  • mfpcopine
    mfpcopine Posts: 3,093 Member
    There's no way, short of being tested in a lab or special gym facility. Use your HRM to see how fast your heart is beating, nothing else. Ignore the calorie burn estimates on machines. Track your calories, keep a record of the frequency, length, and intensity of your exercise and see if you lose weight.
  • redlady82
    redlady82 Posts: 43 Member
    What kind of elevation or resistance do you have? 55 rpms isn't that taxing for a workout so 100 might not be too terribly far off. Also, are you using quickstart or entering age and weight?
  • ejbrin
    ejbrin Posts: 20
    Unless you exercise in a laboratory setting, there's not really going to be an accurate way of measuring your calories (sorry!) I think the machines in the gym tend to be a little more accurate than the MFP calculators, only because every machine is different and there's no way to account for the resistance or include on MFP.

    Depending on the manufacturer, you may be able to find the formula they use and maybe be able to determine a more accurate count with your age, weight, gender, resistance, time, etc. But that'll probably involve a lot of effort and more math than I'm willing to do.

    That's about all the alternatives I can think of without buying a HRM.
  • mfpcopine
    mfpcopine Posts: 3,093 Member


    I'm afraid of entering too many calories burned, but I'm also concerned about burning a lot and not accounting for them and then not really eating enough.
    Thanks!

    For the millionth time, eating too little is unlikely to be one of your problems. Eating too much, especially because you underestimated calories consumed and overestimated calories burned will be, however.
  • LadyBeryl
    LadyBeryl Posts: 344 Member
    I stopped relying on MFP when I found them overestimating -- by more than 3 times -- the amount of calories I was burning. IMO, it is better to underestimate when you are trying to lose weight.

    The inflated numbers often give people a false optimism and this is detrimental when they "eat back" the calories they burn! Personally, I don't do that but I read here where a lot of people do and are encouraged to do so.
  • dsjohndrow
    dsjohndrow Posts: 1,820 Member
    The only accurate way to know what you are burning is metabolic testing. Even the best heart rate monitors are not accurate. What they are good for is a guide. They will give you more consistent results than the MFP calculators. I use and HRM and just put in a time that come close to what my HRM says. I find gym machines and MFP exercise totals to be higher than I get with the HRM for a lot of things.

    How you burn calories is a bit different for everyone, and of course age, weight, genetics, diet and rest all factor in to the equation.

    Because food is 80%-90% of the program, I would invest in a food scale before you get an HRM.

    In the end, if you are losing weight according to your plan, you are probably close. If not, you need to adjust your plan.
  • kellimr
    kellimr Posts: 69
    I stopped relying on MFP when I found them overestimating -- by more than 3 times -- the amount of calories I was burning. IMO, it is better to underestimate when you are trying to lose weight.

    The inflated numbers often give people a false optimism and this is detrimental when they "eat back" the calories they burn! Personally, I don't do that but I read here where a lot of people do and are encouraged to do so.

    ^ Totally agree with you! I couldn't believe what MFP said people were "burning" with their workouts!!?? I had never seen those kind of estimates on any other nutrition or exercise calculation site. I don't log my exercise on here because of that.
  • cncrafton
    cncrafton Posts: 82 Member
    For the millionth time, eating too little is unlikely to be one of your problems. Eating too much, especially because you underestimated calories consumed and overestimated calories burned will be, however.

    Well, it's not uncommon for me to eat like 1,300 calories a day, so I do want to be careful because hovering around 1,000 is not sustainable or healthy for me.

    Anyway, my resistance changes – I use an app on my phone that guides my workout. 55 is what I'm thinking the average would be – sometimes it's 65 at 5% resistance, sometimes the recovery is 45 at 25% resistance, etc.
  • lessfatmatt
    lessfatmatt Posts: 27 Member
    There really is no such thing as 100% accurate measurement (of anything). Even measurements in scientific experiments have some quantity of measurement error (even if it's tiny in some fields).

    The best you can do is choose the measurement device that likely has the least error. For ellipticals I'd usually go with the readout from the machine [rather than the MFP database, if those are your two options] - yeah it will contain some error, but at least it's taking into account your RPM, the resistance levels you've set, and usually your weight. 100 kcal in 30 minutes is not totally unrealistic if your RPMs and resistance levels are both very low. On the other hand, the value the MFP database gives you is just a very rough estimate not taking into account any of those factors.
  • kfdunn
    kfdunn Posts: 14
    A quick sanity check is to compare your elliptical effort to walking/running. In rough terms, your weight in kg (pounds x 2.2) times the distance in km (miles x 1.6) is pretty close to (kilo)calories burned.

    Most people walk ~3 mph unless they're really humping; if you're expending about the amount of energy as a walk, that's roughly 2.5 km in 1/2 hour. If you weigh, say, 75 kg, then you've burned about 190 calories. You can do the math for your actual weight & perceived exertion (the actual formula is kg x km x 1.036 & it's for running, but it's close enough for walking - it's a good estimator for other things, as you can pretty reasonably compare your exertion to walking rates... so, it's a formula worth memorizing).

    Getting to 581 cal would require a 75 kg person to expend the same effort as running 6 1/2 minute miles - an impressive fitness level... so, that 581 probably IS too good to be true for a 1/2 hour workout. To compare, my 5 mile lunch run burned just under 800 calories & I weigh 210 lb... :-/
  • davert123
    davert123 Posts: 1,568 Member
    Good question and for me, good answers. there is no way you can know for sure. The only way I know is to use various sources of information. In your position this is what I would do. I would exercise on the machine at a medium intensity for 20 minutes and calculate how many cals it says you burned per minute. Also remember how much effort you were putting into it. The go outside and walk about a mile at the same intensity level (just on how you feel inside). Time the walk, There are some calculations on the internet which calculate how many calories you will burn per mile for your weight - then just calculate how many calories per minute you burned from this - compare the two numbers (the one you have just calculated for walking against the one from the machine and see how they compare. The walking number will be reasonably accurate and its a good way how to calibrate everything. I agree that HRMs are ok but I am dubious because they are just guessing and there is no way they can be that accurate - if i was superfit my HR would be lower wile running 8 mph than it is when I am running 5 and although I would really be burning far more calroies (perhaps a factor of 2 more) doing the 8 the HRM would tell me I was burning more doing 5. Even if it tried to compensate for fitness it is still at best only a guess. The thing is we are all different and unless you hook yourself up to lots of complicated equipment in a lab that measures your CO2 levels and other chemicals (which are the byproduct of the energy you are converting) everything is going to be a guess.

    after a while you will know another more accurately another way - you will loose a lb for ever 3600 cals you use. If MFP is guessing correct you will loose the weight (on average over a couple of months) that it predicts. If after a couple of months you are not then you can manually adjust the settings. Don't do this after a week or 2 though because there is natural variation in our weight which would make an assessment like this very inaccurate)

    good luck with getting to your goal. The most important thing I've found isn't the accuracy of the calorie count - its keeping at it and tweaking what I do along the way :-)
  • marycmeadows
    marycmeadows Posts: 1,691 Member
    I wear a body bugg all day to track my daily calorie burn.... I know there is still room for error but it seems to be pretty accurate. I'd rather see my total calorie burn for the day vs only what happens when I work out.
  • danambaumgartner
    danambaumgartner Posts: 1
    okay to all the people saying you shouldn't eat back your workout calories or that eating too little will not be a problem THAT IS SOOO FALSE!!!! Your projected NET CALORIES should be just that: NET CALORIES. Your body burns more calories than you think just LIVING! If you start giving your body less than around 1200 NET CALORIES (Calories eaten-calories burned=1200) then you are literally starving your body. Your body will then begin to expect you to starve it and it will store more of what you eat as FAT and you WILL NOT see PROGRESS!! Here is a link to a post which explains it more extensively:
    http://www.myfitnesspal.com/blog/PrayerofAmity/view/to-all-my-friends-who-are-netting-less-than-1000-calories-and-wondering-why-they-aren-t-losing-weight-399342

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