Calories burned don't make sense

kdhartle

I'm a cyclist and train with a heart rate monitor all the time. Here's what doesn't make any sense though. When I log activity here based on time and average speed it tells me I burned 1,000 or so calories an hour. When I load my data to Garmin Connect or Strava it shows that I burned half of that. Anyone have any ideas why this might be?

TheVirgoddess

Because MyFitnessPal generally overestimates calories burned for pretty much everything.

I log all my exercises here, but I cut the time spent on the exercise in half - I'd rather be under the burn than over.

vorgas

Because most cycles have gears and allow you to coast.

NoelFigart1

You can sync Garmin connect here, ya know. I'd run with those numbers. They're probably closer to accurate.

MeanderingMammal

kdhartle wrote: »

When I load my data to Garmin Connect or Strava it shows that I burned half of that. Anyone have any ideas why this might be?

Broadly MFP is approximating based on some pretty broad criteria; time and speed. Your Garmin device picks up the actuals of speed, changes in elevation and if you're fitted your HRM, cadence sensor and power meter. So far more inputs that should generate a more realistic approximation.

Whilst in principle you'll also have periods of coasting in practice that's not going to make a huge difference to the measured expenditure.

Liftng4Lis

TheVirgoddess wrote: »

Because MyFitnessPal generally overestimates calories burned for pretty much everything.

I log all my exercises here, but I cut the time spent on the exercise in half - I'd rather be under the burn than over.

Bingo!

bwogilvie

TheVirgoddess wrote: »

Because MyFitnessPal generally overestimates calories burned for pretty much everything.

^ THIS. MFP's database appears to use the data from the Compendium of Physical Activities, which in turn draws on many studies of how many METs various activities use.

However, the Compendium's MET values presume that there's a 1:1 relationship between body weight and energy consumption. That's generally true of some activities such as walking and running, but much less true of others, including cycling. The calculator at BikeCalculator.com is instructive. When you're cycling over 12 mph, wind resistance is the main force that you have to overcome (except on hills), and it is proportional to the surface area that the rider and bike present to the wind, not weight (in fact, heavier riders with more muscles and momentum have an advantage over lighter riders when going against a stiff wind).

I find that MFP's estimate is only about 5-10% over what my Garmin Forerunner 620 estimates for my runs, but it is 30-70% higher than what my Garmin Edge 800 estimates for my rides.

WalkingAlong

I would think they'd use the compendium but then they have estimates like pushing a stroller burns FEWER calories than walking unfettered, which the compendium doesn't show.

bwogilvie

WalkingAlong wrote: »

I would think they'd use the compendium but then they have estimates like pushing a stroller burns FEWER calories than walking unfettered, which the compendium doesn't show.

I think users can add activities, as with the food database.

JoRocka

TheVirgoddess wrote: »

Because MyFitnessPal generally overestimates calories burned for pretty much everything.

I log all my exercises here, but I cut the time spent on the exercise in half - I'd rather be under the burn than over.

this.

And if it bothers you- I would recommend switching to TDEE method and just fold in your workouts to your food plan.

Hornsby

Figure 500 per hour for cycling and you're golden in my opinion.

PAtinCO

TheVirgoddess wrote: »

Because MyFitnessPal generally overestimates calories burned for pretty much everything.

I log all my exercises here, but I cut the time spent on the exercise in half - I'd rather be under the burn than over.

What I've always done is count every exercise as walking, 3mph. It seems fairly accurate if you are actually walking and everything else you do burns more so I come in under most of the time.

Mr_Knight

MFP's estimates for walking are about 2x too high, because they don't back out BMR, meaning you're double-counting a huge portion of the calories. However, because walking is such a low burner relative to other forms of exercise, using MFP's walking numbers as a proxy for those other exercises is actually not a bad idea. :drinker:

PAtinCO

That's interesting. I've always gone by the rule of thumb that walking a mile is 100 calories for the average sized male, which is me. So 3 mph = 300 calories which is what MFP puts it at when I log. If that includes the BMR though, then walking a mile is actually closer to 50 calories burned in excess of what you would normally burn just sitting?

That's something I don't think I had considered. Good to know.

TheVirgoddess

Mr_Knight wrote: »

MFP's estimates for walking are about 2x too high, because they don't back out BMR, meaning you're double-counting a huge portion of the calories. However, because walking is such a low burner relative to other forms of exercise, using MFP's walking numbers as a proxy for those other exercises is actually not a bad idea. :drinker:

I didn't know this! I use my FB to track steps, so I don't log walking, but this is good information to have.

Rabid_Hamster

the MFP time and calories is based on an average person. (I don't know the exact algorithm). Assuming you bicycle regularly and longer distances, your heart is probably in good/great health and therefore lower than the "normal" model. Since you have a heart rate monitor, I recommend you use that entirely since you've personalized it to your specs.

missomgitsica

MFP overestimates. Go with your HRM. I don't understand why this is even a question . . . if you're not using the HRM calorie burned estimate, why did you get an HRM to begin with?

Mr_Knight

missomgitsica wrote: »

MFP overestimates. Go with your HRM. I don't understand why this is even a question . . . if you're not using the HRM calorie burned estimate, why did you get an HRM to begin with?

Heart rate and calorie burn do not, under most conditions, correlate very well. HRMs guesstimate calorie burns, and for most people, doing most exercises, they significantly over-estimate the burns.

peter7361

PAtinCO wrote: »

That's interesting. I've always gone by the rule of thumb that walking a mile is 100 calories for the average sized male, which is me. So 3 mph = 300 calories which is what MFP puts it at when I log. If that includes the BMR though, then walking a mile is actually closer to 50 calories burned in excess of what you would normally burn just sitting?

That's something I don't think I had considered. Good to know.

Generally, walking at a normal speed on a level ground will burn 0.3 calories per mile per pound of body weight. So if you weigh 200 pounds, you'll burn 60 calories per mile you walk. It's not exact, as different people will have varying efficiency in their muscles, joints, and cardiovascular system that may cause the number to vary slightly, but it should be very close to that number.

sweetdixie92

Hornsby wrote: »

Figure 500 per hour for cycling and you're golden in my opinion.

Not necessarily...depends on your weight and physique.

But anyways, I'm a biker too. While I typically average 18-19mph on my rides (that includes a lot of hills), I actually log it as "Biking, 14-16mph".

WalkingAlong

bwogilvie wrote: »

WalkingAlong wrote: »

I would think they'd use the compendium but then they have estimates like pushing a stroller burns FEWER calories than walking unfettered, which the compendium doesn't show.

I think users can add activities, as with the food database.

I never knew that! Crazy! I made an activity called 'pushing a treadmill'. Can others see it? It doesn't even have an asterisk or anything? Does it give others the 150 calorie for 30 minutes or whatever nonsense I put in there or does it at least scale it for BMR differences?