% accuracy of MFP calorie burns

ovi212

I always see people saying how MFP severely over estimates calorie burn for exercise. I've seen recommendations to only log 50% of the time done, or only eat back 1/3-2/3 of the calories it gives you.
Obviously having a HR monitor on would be the best solution but for those who can't I was wondering if anyone who wears one ever calculated the % accuracy of MFP?
What would you recommend logging? Is it 50% correct usually? 25%? 75%? Are some activities more accurate than others?

aswearingen22

Here's a real world example. I ran 4 miles today and according to my HRM (Garmin 610), I burned 392 calories. Logging that run in MFP, it would give me 472 calories, an overage of 17%. And a 4 mile run is the shortest run I do all week, so it'll only get worse the longer I run. For instance, I ran a half marathon a few weeks ago and actual calories per my HRM was 1,522. MFP would give me 1,890, a difference of 368 or 20%

When logging 30 Day Shred, on my HRM, I've burned somewhere between 171-203 depending on the day, so we'll say average 187. If I log this under circuit training in MFP, it will give me 252 for 26 mins, a difference of 26%.

MFP always gives me more than my HRM, but it's not always consistent, and I really imagine it matters how much you weigh, exactly what you were doing, etc. I would suggest just spending the money and getting a Polar (I think some are as cheap as $60ish) or a Garmin (if you run, that would be around $100+ for the base model).

ovi212

Thanks!
As a student I can't afford one, but it seems like I could be pretty safe logging 50% of the time I spend.

cwolfman13

Given the sheer number of variables involved, the % error is indeterminable and will be different from individual to individual. To boot, much of the error is user error in that people tend to overestimate their level of effort when inputting data into these databases and various online calorie burn calculators.