Calorie Burn Calc - Garmin/Nutrisystem HUGE dif?

[DogHermit]

I just started Nutrisystem, and also just switched from running to biking after about 6 months off due to an injury. Today I took a short ride (6.5 mi) with my Forerunner 305 on the handlebars, and when I got home I dumped the GPS into my PC. Then I went into the Nutrisystem website and logged my exercise for the day. And... wow!

Nutrisystem's calculator says that after 30 minutes of biking in the 12-14 mph range, I should have burned about 281 calories.

The Garmin dump says I probably burned about 1070!

What gives here? This is a huge difference! When I work on an elliptical for an hour it usually calculates about 700 calories burned, staying in my heart zone of 140 bpm. On a stationary bike for half an hour, about 300 calories.

I'm inclined to believe the Nutrisystem calculations based on my elliptical/stationary bike data, but I'd love for someone to set the record straight here. I'd be bummed if this expensive GPS is that far off...

Thanks for any thoughts - tDH.

[jlcharles]

Does the garmin have cadence? I'm sure it takes that into account along with your hills and all. I'd be more inclined to trust the garmin as it has much more data to work with than just your speed.

[wrk101]

Sounds like the Garmin is way off.

[bautieri]

Garmin is off by a long shot. Figure you burn an average of 33 calories a mile. More if your pushing hard, less if your slacking.

Is your Garmin set to feed back calories or Joules?

[japollner]

The Garmin may be factoring in elevation among other things. Who knows.

I would be hesitent to trust anything short of a powertap that measures actual power generated by the legs.

[Michaelbe]

That's a huge difference. Did you forget to reset the Garmin? Perhaps it added this workout with the last.

Michael

[hammond9705]

Garmin greatly overestimates compared to my powertap. Garmin has me at about 100cal per mile, and the powertap has me at 40-50 per mile. I believe the powertap. Like you I compare it to the treadmill at the gym, and I know that it is really hard to burn 1000cal/hour. The Garmin would have me at about 1500cal/hour if you believed it.

[jaxgtr]

Garmin calorie count being high is a known issue. It is ridiculously high and I think the gov't has had the FBI labs trying to figure out how they calculate it. :p

[sstorkel]

Nutrisystem's calculator says that after 30 minutes of biking in the 12-14 mph range, I should have burned about 281 calories.

The Garmin dump says I probably burned about 1070!


The Nutrisystem result sounds pretty close to why my Polar heart rate monitor tells me when I ride at a similar pace. The Polar I have seems to be more conservative than just about anything else I've tried. I don't see 1000 calories unless I've been riding for an hour and a half and pushing the entire way (17+mph on flat ground). I take all of these numbers with a grain of salt, especially any machine at a health club; there's too much incentive to inflate the burned calorie number...