TrainingPeaks kcal Calculation

Triathlon Forum
1

Anyone know how accurate the TrainingPeaks Kcal numbers are for swim, bike, run?

I am counting my calorie intake to loose those elusive last few pounds and want to find my calorie expenditure from my workouts to account properly. First I am curious as to how accurate people have found those estimates to be, and second, I am noticing a discrepancy between the calculation of calories single workout (2 separate files).

Last night, I did a ride on trainerroad where my power was recorded on both my Garmin 500 and the trainerroad app. My Garmin 500 had dropouts so I uploaded both files and there is a big discrepancy between the calories calculated for this workout in TP between the two files, but not a big discrepancy in the KJ. Here is a summary of the data:

Garmin 500:
Time: 1:06:27
KJ: 835 (797 over the first 60 min which is the time that Trainerroad recorded)
KCal: 517
*This file includes speed and HR, the TrainerRoad file does not. This file is longer due to the extra cool down I did, which TR did not record.

TrainerRoad File:
Time 1:00:00
KJ: 827
KCal: 818
*This file includes power data only.

This seems like a huge variance in the calories calculated, even though the total output was similar. I am wondering if one of two things is happening. First perhaps the KCal calculation on the 500 is coming from Garmin and not TP. Second, perhaps TP is using HR and not power to calculate the calorie expenditure. Thoughts?

2

If you using a power meter then the calorie estimate will be reasonably accurate as it is measuring work done. There is still quite a large variance possible though. When running both Garmin, and TP use a formula based on your weight. If you wear a HR strap it will use that to see how hard you are working. These are pretty unreliable estimates. Swimming it just makes it up as it goes along.

I lost a lot of weight last year. I generally took the estimates from garmin and ate back about 75% of cals that they told me. That seemed to work for me. Some days if I felt I lacked energy or more hungry I would eat a bit more.

Its trial and error. Try eating back all and see if you lose weight, if not eat a bit less.

Dont forget as well that the calories given on food are allowed to vary by about 15% (in UK) so its not an exact science