Is MFP double counting my Basal calories for excersise?

MrFitFrank

Let me paint a picture of exactly what I'm asking.

Let's say a person's BMR (Basal Metabolic Rate) is 2400 cal per day. So taking a simplified view this person burns 100 cal per hour (I know the burn is dependent upon your level of activity but let's keep it simple for now).

Now let's say this person does a bit of moderate cardio for 2 hours and at the end of the cardio session sees (using their heart rate monitor i.e. Polar, Garmin, etc) that they've burned 300 cal in the two hours. They log the excersise on MFP and MFP rewards them with a potential 300 cal to eat for the day.

To me it seem MFP should have said, 2 hours at 100 cap per hour means your BMR for the 2 hour window is 200 cal so in effect you've burned 300 cal (excersise) - 200 cal (BMR) = 100 cal Nett. And then reward you with the 100 cal instead of the 300 cal.

I'm I onto something here or missing something in my grasp of BMR vs Activity?

ChrisM8971

In my view yes, which is why even with an HRM this can be trial and error. If you use the reading from the HRM and you are not losing at the expected rate then reduce the calories that you input for exercise.

However the a BMR of 2400 would be very high (closer to a TDEE figure which includes exercise)

MrFitFrank

Chris, thanks for the reply. I'm glad to hear I'm not alone in this line of reasoning. As a rule of thumb I try and never eat more than a third (33%) of the calories I burned in exercise during the day; over and above my daily calorie goal.

Yes the 2400 cal BMR is quite high, I picked 2400 because it simplifies the math. My BMR is closer to 2000 cal.

woofer00

I find machine reporting high. Logging and relying on that tends to set me backwards. I subtract at least 100 cal/hr from whatever the cardio machine reported. If I had my fitbit on me, the offset calculation takes care of some of it, but I usually leave that in the locker at the gym.

LaurenAOK

Your observations are correct, but in most cases it's not going to make as big of an impact as in your example.

For example, my BMR is around 1400, so about 1 cal/minute. If I do a 60 minute workout that burns 400 calories, I only need to subtract 60 calories for BMR purposes, leaving me with a "real" exercise burn of 340 calories. That's more than 3/4 of the calories MFP would credit me with, so it's a small enough difference that it doesn't bother me.

Now take someone who is taller and/or heavier than I am. They are going to have a higher BMR, so the subtraction amount is higher. However, they are also going to burn a lot more during exercise than I do - so proportionally, their "real" burn should actually be pretty similar to mine.

Basically, don't overthink it. You're technically right, but most people on this website eat the cals credited by MFP and lose weight as expected. I eat about 75% of my exercise cals to account for overestimation, and haven't had any trouble losing.

Oh, and if you have any interest in getting a Fitbit, I've been told they do take this factor into account. So the TDEE it shows you at the end of the day will include your exercise cals, but minus the cals you would have burnt during that time just sitting around. If you're really nitpicky about accuracy, a fitbit may help you feel more sure about things.

woofer00

One more thought - odds are, few people are burning upwards of 3k calories per week just on cardio machines. I do, but I cardio to de-stress after work out of habit. If the calorie burn report is off by 10% or even up to 25%, that's 300-750 calories a week. Assuming 3500 calories per pound (MFP's assumption, for what that's worth), that's 0.1-0.21 lbs of variance. There are so many other margins of error in calorie counting that it's not that big a deal. You're probably still headed in the right direction.

robertw486

I think quite a few apps and devices overestimate BMR grossly. As stated above I really don't worry about adjustments within reason, and usually don't even bother to make them. But where possible I find apps that report closer to net calorie burn when I can.

Using Endomondo it was adding calories to the extent of 3,200+ when I was less than 190 lbs. That extra 136 calories per hour would add up quick during the summer when I exercise a lot, and easily eat up a deficit if I was losing weight and not accounting for it.

I did some testing of apps and Strava vs Endomondo was very close in calorie burn if I subtracted that crazy BMR Endo was adding. But for me it's easier if the apps that connect report the net.

We also have an elliptical, and it seems to report gross. I should do some testing based on METS (since it outputs MET value) and figure out what it adds for BMR.

MrFitFrank

Woofer00, LaurenAOK and Robertw486, thank you for your posts. I really appreciate the detail and perspective articulated in your posts.

Not over thinking it is sound advice, I have to admit the Scientist in me can't help but explore the math behind all of this.

robertw486

It is a good catch. For some not noticing things like that could really mess with their weight goals. And if you use the wrong app, it gets really tricky if you exercise a lot.

When time allows, I sometimes burn at or near 1000 calories a day. That error can really add up, positive or negative.

ninerbuff

Your math is wrong. You stated 100 calories per hour, but if someone burned 300 calories in 2 hours, that's an average of 150 an hours. So you shorted 100 calories somewhere.
Anyway, if someone was at hypothetically at 2400 BMR, the if they NETTED 2400 at the end of the day, they would neither gain nor lose weight.
Here's a confusing way to screw up math:

Three students checked into a hotel and paid the clerk $30 for a room ($10 each). When the hotel manager returned, he noticed that the clerk had incorrectly charged $30 instead of $25 for the room. The manager told the clerk to return $5 to the students. The clerk, knowing that the students would not be able to divide $5 evenly, decided to keep $2 and to give them only $3.

The students were very happy because they paid only $27 for the room ($9 each). However, if they paid $27 and the clerk kept $2, that adds up to $29. What happened to the other Dollar?

A.C.E. Certified Personal and Group Fitness Trainer
IDEA Fitness member
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Been in fitness for 30 years and have studied kinesiology and nutrition

amymeenieminymo

As others said, you're technically right. For a time I was subtracting out the calories I would have burned anyway sitting on the couch. But the downside to that is, it can mess with your head. If I really worked hard and burned 350 calories on the treadmill, it was a real morale killer to have to say I really only burned 280 or whatever. Not being able to log whatever my HRM said sometimes made me say screw it and I ended up over eating, or not even bothering to work out some days.

Something else I also took into account is whether or not you turn off your HRM the second your done exercising, or letting it go until your HR returns to it's normal resting rate. I made a deal with myself, I would log the exact amount that my HRM said, but I would turn it off the minute I was done, despite my HR still being pretty high for a while. But like others said, if you notice you're not getting the results you desire, you could always make the adjustment and see if it helps. For me, I still saw results even with eating back my BMR amount.

MrFitFrank

Robert, I had a freakish day (at least for me) yesterday resulting in 2,563 cal burnt during 325 min of activity. So both the size of the cal involved and the duration definitely plays into it all adding up.

Ninerbuff, thanks for your post. I'm not quite sure what you mean with 100 cal shorted though. I was putting forth the assertion that the 100 cal shorted you refer to should be the only cal(s) logged in MFP as not to double count the 100 cal/hour (200 cal in total) attributed to BMR. As for the missing dollar. Nice framing bias creation. The reality is that the students paid $27 of which the clerk pocketed $2 and the remaining $3 is safe and sound in the students wallets.

Amy, thank for your post. I too committed to stopping the HRM as soon as the excersise was complete irrespective of where my HR is at. I do however have one exception to this rule. Any fitness class I go to I let the HRM run for the official length of the class (i.e. 45 min for Spinning) irrespective of whether we wrap up early or late. I find having a cal total over fixed time in this regard to be quite informative as to the effort I exerted in the class. Lastly, to your point of low cal being a morale killer I have to confess I'm a bit lucky, being a 6"2 male I tend to burn cal(s) well above average so that really hasn't been a problem thus far. I can say that as my fitness increases I find with the lowered Average HR my cal(s) burned obviously falls. I think the advice I'd give myself if this particular morale killer ever presented itself would have to be: "Sure, I would love higher cal(s) but I'm for damn sure doing better than I would if I where sitting on the couch".

robertw486

fschonken wrote: »

Robert, I had a freakish day (at least for me) yesterday resulting in 2,563 cal burnt during 325 min of activity. So both the size of the cal involved and the duration definitely plays into it all adding up.

That's the kind of thing that drove me here. I lost weight without counting calories as the more active I am the more I tend to watch what I eat. But I reached a point where I wanted to make sure I was eating enough back on the high energy days so I wouldn't be tired or not have enough nutrition for good recovery.

It's taken some time but eventually I've figured out some decent apps and sources for calculating energy burns close enough for what I'm doing.