# Garmin Connect Calorie Calculation



## Alaska Mike (Sep 28, 2008)

OK, I know the standard anser is that Garmin calorie calculations are flawed, but here goes:
Today I am 185lbs. I did one hour on the trainer averaging 226W (228W NP), just cruising along and doing 817kJ. Average HR was right about 150 BPM (max is around 187).
I zeroed the Quarq before the workout as always, and downloaded the workout afterwards into Garmin Connect. I also use WKO+, but it's easier to share snapshots of workouts with my coach this way without us having to pay for memberships. She gets the WKO files at the end of every week.

Anyway, the Calories burned for today's workout according to Garmin Connect is 688C. How is that calculated? I know a lot of people use the kJs done, but that's a 15% difference.

This is for my own curiousity, since I will likely use the smaller of the two numbers. I'm trying to drop some weight by race season, and every little bit helps. It just seems odd that the calculations can vary so much.


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## Kerry Irons (Feb 25, 2002)

Alaska Mike said:


> OK, I know the standard anser is that Garmin calorie calculations are flawed, but here goes:
> Today I am 185lbs. I did one hour on the trainer averaging 226W (228W NP), just cruising along and doing 817kJ. Average HR was right about 150 BPM (max is around 187).
> I zeroed the Quarq before the workout as always, and downloaded the workout afterwards into Garmin Connect. I also use WKO+, but it's easier to share snapshots of workouts with my coach this way without us having to pay for memberships. She gets the WKO files at the end of every week.
> 
> ...


Assuming 24% metabolic efficiency (a widely reported number for fit athletes) then the conversion is 3.6 calories per watt-hour. Of course without detailed metabolic analysis nobody actually knows their metabolic efficiency but it seems that many calorie calculators (and those ignorami at Bicycling magazine) use numbers closer to 18% and that is why their numbers are wildly high. It does make their customers feel better about themselves.


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## looigi (Nov 24, 2010)

At 165 lb, I just figure 600-700 cal/hr avg. Some rides may be higher and some may be lower, but over time that's a reasonable average. If I'm riding/training 7 hrs/week, I add 4200 calories to my basal rate, so instead of 2000 cal per day I eat 2600/day. I find this works better for me than trying to match my burn and intake day by day. I watch my weight and if it starts going up over time, I cut back a few hundred cal/day until it comes back in line. My weight will fluctuate +/- a couple of pounds due to hydration/glycogen status.


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## Dave Cutter (Sep 26, 2012)

Alaska Mike said:


> ...... It just seems odd that the calculations can vary so much.


A well trained cyclist on a modern multi-speed bicycle achieves much greater efficiency's than an overweight grandma on a balloon-tired cruiser with a basket on the handlebars. But then.... grandma may not have a coach to share training stats with ether.

The CDC sets the standard for health and fitness creditability. It would be hard to turn your back on the basic standards they provide as "truth" to the public and fitness industry. Yet... those figures don't relate as well to specialized athletes.... as they do to an over-weight general public.

Trained, efficient, cyclists will burn far fewer calories than any of the charts. 

Using the charts to help predict a weight-loss time schedule is do-able. Figuring 3500 calories equaling one pound for food _and maybe 5000 calories burned cycling per pound_ for weight loss. But if you are trying to calculate in a way to eat a greater amount of food by increasing exercise it won't work. IMHO... you can't pedal off the pounds.

Again... IMHO.. trying to calculate an exercise to weight loss figure might be the first step to discovering a very destructive eating disorder. I always track my calories burned... pretty much in the same way I track outside temperature and the names I assigned to the various routes I ride. 

Unless your riding thousands of miles and huge numbers of hours on your bicycle... dietary needs shouldn't be a bigger deal than your coach can deal with. In which case consulting a nutritionist would be the next step.


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## Alaska Mike (Sep 28, 2008)

Don't get me wrong- I'm going with the lower of the two estimated caloric expenditures. I just found the difference between the Garmin estimate and the reported kJ interesting, especially given the common advice to just use the kJ number as a direct conversion to calories burned. I'm shooting for a 500 calorie/day deficit for what I've found to be a sustainable weight loss track. Any more and I usually regain quickly, any less and I plateau quickly. Would 100-150 calories really make a difference? I doubt it. I was just curious.

I'm going with a strictly calories in-calories out approach. My actual diet could be better in terms of types of food, but I'm going with a slow evolution instead of going cold turkey on the stuff I enjoy from time to time. If I want to go to McDonalds once in a while, I'm going to go. I'm just going to make different choices when I'm there about what and how much I eat, then adjust other meals to atone for my sins.

I'm not in danger of being picked up by Riis anytime soon, and have no great aspirations beyond my own small little racing pond. I just want to drop a few so maybe I can climb a little better, then maybe sustain that weight for a while instead of bouncing back up after the season is over. What I'm shooting for is to be at a "normal" weight according to the BMI scale, something I haven't been in over a decade. I've been hovering about 6-12lbs over for the last few years, and I'd like to be comfortably at a place where most people would consider me skinny (using the Walmart, non-meth standard).


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## arai_speed (Aug 19, 2003)

Here is a link to a great article on this subject:

How calorie measurement works on Garmin fitness devices | DC Rainmaker


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