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Apple Watch not good at calorie counting ?

S

soamz

macrumors 6502a
Original poster
Jun 20, 2010
704
8
Orissa, India
It seems Apple Watch is not very accurate or just not accurate at all, I would say.

I have a brand new Apple watch 2 and for the same workout, it shows like 180 calories while my fitbit and other measurements thing shows perfect 350 or so.

Its just not this single case. I have tested with everything running walking everything, it counts almost 4 times less calorie.

Whats the issue ?
 
It’s based on heart rate, what does the Fitbit use? The heart rate monitor isn’t super accurate though, use a chest strap if you want that. Also make sure the watch is tighter than usual during a workout, I’ve had to position it right over the vein in my wrist to get more accurate readings as well.
 
How do you know the Fitbit is perfect because it shows 350?

Any calorie tracker is an estimate with a huge number of variables. As long as any device is consistent between workouts i think that’s all we really need.
 
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Strelok said:
The heart rate monitor isn’t super accurate though, use a chest strap if you want that.
Click to expand...
Having worn a chest-strap based watch HRM at the same time as the optical HRM through many workouts, my experience is the optical is *very* close. Generally within 1 BPM and never more than a couple BPM off. It's frankly rather surprising how accurate current optical HRMs really are when you consider how they work. The one thing that will regularly throw off a wrist-worn optical HRM is an activity in which you're tensing your wrist.

Julien said:
Are your personal metrics setup (correctly)?
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Good suggestion. That's the usual reason for caloric measurements to be way off. Different devices will often be a little ways off, but the level of discrepancy shown suggests some personal metric isn't set up correctly -- though it could be on either device. The usual culprit IMHO tends to be HRmax and people using that stupid formula instead of getting out and actually sweating their way to a HRmax estimate.
 
I find Apple Watch is slightly less than Fitbit & Garmin for total calories but IMHO that is more accurate. What sometimes confuses people is Apple likes to present ACTIVE CALORIES for a workout front and center and sorta hide the total calories. Apple's "ACTIVE CALORIES" are the calories burned due to motion NOT due to the act of being alive. During a 1 hr workout you burn calories because of the workout AND calories due to being alive and Fitbit & Garmin show the sum total of both of those. Apple breaks it out to show just what movement accounted for and you have to search for total calories to see the Fitbit & Garmin like numbers.
 
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canyonblue737 said:
I find Apple Watch is slightly less than Fitbit & Garmin for total calories but IMHO that is more accurate. What sometimes confuses people is Apple likes to present ACTIVE CALORIES for a workout front and center and sorta hide the total calories. Apple's "ACTIVE CALORIES" are the calories burned due to motion NOT due to the act of being alive. During a 1 hr workout you burn calories because of the workout AND calories due to being alive and Fitbit & Garmin show the sum total of both of those. Apple breaks it out to show just what movement accounted for and you have to search for total calories to see the Fitbit & Garmin like numbers.
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Well said.

If you want to look at the day's calories, go into the Activity app in the iPhone. In the Move Ring graph, swipe left and you'll be presented with the detailed calorie burn for your day. It is detailed as Total Calories and Active Calories. Obviously, the total one should be mugh higher as it takes into account average calorie burn for specifics based on your height and weight.
 
IMHO, I think that the apple watch is more accurate than other calorie counters out there. I like that it displays "Active Calories" and "Total Calories".

For example, I have a treadmill that I sometimes jog on, and it'll say that I burned 400-500 calories in a 30 minute jog which is likely incorrect. The Apple watch would likely show closer to 250 active calories which makes a lot more sense given my height, weight & age.

Even when factoring in "total calories" on the watch, it still isn't anywhere close to the 400-500 calories listed on the machine.

As such, I really think that a lot of devices over-inflate calories burned.

When I had my Galaxy S7, I used the health app on there to track my jogging outside, and it too said I burned closer to 450 calories over a 5.5KM run, which again, given my age, weight and height, isn't likely. The apple watch would say closer to less than 300 active calories which probably makes more sense.

Furthermore, no one really knows for sure how many calories are being burned... these are all just guestimates. But it's likely lower than you think.
 
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Suspenders said:
IMHO, I think that the apple watch is more accurate than other calorie counters out there. I like that it displays "Active Calories" and "Total Calories".

[...]

Furthermore, no one really knows for sure how many calories are being burned... these are all just guestimates. But it's likely lower than you think.
Click to expand...

Excelent post. Couldn't agree more. But one one thign I digress. We can measure calories. After all, a calorie is the unit of energy it takes to heat 1 gram of pure water by 1*C. A calorimeter can be used to know the exact calories burned.

We can convert that into joules (unit of energy) which can be translated into Watts. In Watts you can estimate it based on the run speed of your motor at your jogging speed.

Sorry, let my inner nerd go.
 
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jav6454 said:
Excelent post. Couldn't agree more. But one one thign I digress. We can measure calories. After all, a calorie is the unit of energy it takes to heat 1 gram of pure water by 1*C. A calorimeter can be used to know the exact calories burned.

We can convert that into joules (unit of energy) which can be translated into Watts. In Watts you can estimate it based on the run speed of your motor at your jogging speed.

Sorry, let my inner nerd go.
Click to expand...

Sorry, I agree here and should have been more clear. I think that a lot of machines inaccurately calculate calories burned. But yes, we can actually measure what a calorie is, etc.
 
I've kind of been doing some experimenting to see how accurate the Apple watch is. Everyday when I go walking this month so far, I've been wearing two Apple watches, one series 3 LTE paired to my 7+ and a series 2 paired to my 6S+.

Both have been almost identical with steps, calories and distance. Calories only varied by 4 between the two and the steps, were only off by about 10. It's been that way all three days of this month so far.
 
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KrisLord said:
How do you know the Fitbit is perfect because it shows 350?
Click to expand...

Yeah it's kinda funny to see these threads on here. I think it's a symptom of "I have always assumed the device I've been using for X years has been accurate, so now when I try a new device and it's different this new device must be wrong!!!"

I'm not sure how FitBit does their calibration, but Apple has a pretty intense team testing the Apple Watch for caloric burn so I would think it would be pretty accurate. Everything is just an estimate anyway. I wouldn't put too much stock into the absolute values and instead compare past values to increase or maintain your activity level.
 
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For me personally I really wasn’t losing weight going by the Fitbit calorie burn readout (and logging my food, aiming for -500 or so per day, often coming up short but having a deficit nonetheless). When I changed to Apple Watch and started using THAT calorie burn number and adjusting my eating, I am losing weight/maintaining easier. So I do think Fitbit overestimates, at least in my case.
 
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Calorie counting is nothing more than an educated guess. Figuring in your health stats like weight and your HR, the devices roughly calculate the amount of calories burned. No way I would call it accurate, just numbers that you can use to compare with on a daily basis.
 
soamz said:
It seems Apple Watch is not very accurate or just not accurate at all, I would say.

I have a brand new Apple watch 2 and for the same workout, it shows like 180 calories while my fitbit and other measurements thing shows perfect 350 or so.

Its just not this single case. I have tested with everything running walking everything, it counts almost 4 times less calorie.

Whats the issue ?
Click to expand...
 
It isn't correct to say the "Apple Watch isn't accurate", because it's the software doing the calculations, not the hardware. If you do a run with the Workout app, then sync the same run to Strava and other fitness apps, you will get a different calorie count from the same data. The Watch simply records the heart rate and other metrics, and the software does the calculation - third party or Apple.

If you installed the FitBit app for the watch, you'll probably get a similar count to your FitBit. The Workout app does tend to be on the low side for the number it produces, but many apps I tried were unrealistically high.
 
As of this point today:

Fitbit: 2604 calories
AW: 2663 calories

They seem pretty close.

(Yes, I know this is a zombie.)
 
You can't really compare the calorie count of 2 totally different devices. The algorithms they use are totally different. Calorie burn is just a guess in the absence of a calorometer. Consistency within the same device is all you can really hope for. I was more active today than yesterday so my watch should tell me that I burned more calories
 
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gsucyclist said:
You can't really compare the calorie count of 2 totally different devices. The algorithms they use are totally different. Calorie burn is just a guess in the absence of a calorometer. Consistency within the same device is all you can really hope for. I was more active today than yesterday so my watch should tell me that I burned more calories
Click to expand...
Do you know that, say, Apple Watch and Fitbit use different algorithms?

I agree that different devices don't necessarily need to reach the same answer. As I've said before, what's important here is precision, not accuracy.

However, if two widely used devices consistently give very similar answers, it's pretty hard to make a case that one isn't good at counting calories (measuring caloric burn).
 
Thrifty1 said:
Here was a good study on wearables and heart rate accuracy along with calorie (energy expenditure) burning.

Apple Watch was best for heart rate with only 2% error rate. However it was 30-40% inaccurate for energy expenditure. The best wearable of those tested (Fitbit Surge) was over 20% inaccurate for energy expenditure.

https://res.mdpi.com/jpm/jpm-07-00003/article_deploy/jpm-07-00003-v3.pdf?filename=&attachment=1
Click to expand...

I’m sorry if this comes across as stupid, but energy expenditure? Does that mean it’s bad at calculating your total daily burned calories? Or something else?
 
I posted this on a similar thread, but thought it might help. If not then I apologize.

This is just a hypothesis, so don't crucify me if I'm off here: Many of you are saying that the calorie count now is higher than before, and thereby believeing that it is wrong. Going through the comments it seems that several people utilize the Apple Watch along with other fitness tracking devices, and are reporting that they are either the same or very close. So, given that information, isn't it possible that the way your Apple Watch tracked calories before was actually wrong, but now it is more accurate?
 
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