bodybugg calorie counter readings seem inaccurate
December 30, 2011 11:34 PM   Subscribe

Why is my bodybugg (R) saying I burned 2,000 calories while making dinner?

I got a bodybugg as a gift a few days ago. I immediately registered it online and answered all their questions (what foods do you eat?, what times do you sleep?, are you right or left-handed?, do you like to walk/jog/sit on the couch?).

I put it on my left arm (as tightly as they suggest) and walked around my living room for 2 minutes so it would sense activity. The iPhone app said that I burned 200 calories.

I didn't think this was accurate, so I sat on my couch for 10 minutes and did nothing. It said that I only burned about 10 calories.

I slapped it a bunch of times to see if it would be tricked into thinking I was taking steps instead of sitting on the couch. It wasn't fooled.

I re-read the info on the back of the box to make sure I wasn't doing anything wrong. It said that the bodybugg is 90% accurate.

I decided I must have actually (somehow) burned 200 calories in 2 minutes by simply walking around my house.

The next day, I put the bodybugg on my arm again and made dinner. I came back 45 minutes later to check the iPhone app, and this time it had sensed that I burned 1800 calories during those 45 minutes. I had simply made dinner (not while running a marathon or swimming the English Channel).

What's going on here?
posted by carielewyn to Health & Fitness (10 answers total)
 
Sounds like it's defective. Can you return it for a new one?
posted by tristeza at 12:43 AM on December 31, 2011


Maybe it's reporting cal(orie) instead of K(ilo)cal(orie).
Makes sense you'd burn one or two calories sitting on your couch in ten minutes or maybe 20 calories walking in your house in two minutes, or 180 calories making dinner in 45 min ...
Seems about 90% accurate taking that into account (amount of energy = heat required to raise 1 gram of water by 1 degree C = cal v. amt requires to raise 1 Kg of water 1 degree C = Kcal).
On preview maybe I'm up too late, my math is off by an order of ten ...
Is there a setting for that on the machine? 1 Kcal = 1000 cal

Maybe they're just telling us we all wear a size 6 dress by telling us we are burning so many calories!
posted by bebrave! at 12:56 AM on December 31, 2011 [2 favorites]


If it was cal and not Kcal, 1800 calories is 1.8Kcal. Sounds like something is confusing it.
posted by RustyBrooks at 5:47 AM on December 31, 2011


Just for reference, best estimates indicate that for me (200 lb 6' male), an hour of cycling is about 450-500 kcal, about the same as a half hour of running. To get into the 1800 kcal range I have to do some pretty serious work, 3 or more hours of cycling usually. So pretty clearly you didn't do 1800 calories of excercise making dinner. I guess the question is, did something temporarily freak it out, or is it broken, or is it entirely misadjusted, etc.

I had never heard of the device before now but poking around it does seem like people believe it's accurate to within 15-20% - it doesn't seem normal for it to be off that much.
posted by RustyBrooks at 5:58 AM on December 31, 2011 [2 favorites]


What did you make for dinner? Their Website says that one of the things it senses is body heat (I didn't read too carefully, though). Is it possible it was picking up ambient heat from your cooking?
posted by Gorgik at 6:23 AM on December 31, 2011


Seconding Gorgik. The only way a device you wear would measure calories is to read the flow of heat out of your body.
posted by gjc at 7:40 AM on December 31, 2011


Best answer: There are a number of ways it measures calories coming out of your body. I had the same issue with my BodyMedia (made by the same company) and the representative said it can take time for the device to adjust its calculations to you. If you're still getting weird readings in a week then give them a call. Mine settled down after a couple days.
posted by Anonymous at 8:19 AM on December 31, 2011


Best answer: Also, are you keeping it on the whole day? Because if you leave it off, then it will estimate what you burned for the rest of the day. So you can put it on for an hour, and the 1800 calories probably includes what it estimates you burned during the time you had on. These things are most accurate if you leave them on all the time.
posted by Anonymous at 8:20 AM on December 31, 2011


Best answer: Sorry, during the time you didn't have it on.
posted by Anonymous at 8:20 AM on December 31, 2011


Response by poster: Thanks, schroedinger. I just confirmed with the friend who gave it to me that hers did the same thing. Apparently it guestimated that I burned 1800 calories while I had it off the whole day, because I only put it on at night when I went to make dinner. It kind of makes sense now.
posted by carielewyn at 8:49 AM on December 31, 2011


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