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Body fat %


Just bought the Garmin Index scales as I wanted to track my weight and body fat. 

Problem is the bf% reading is completely off, saying I'm 8%. I knew I was definitely not that low, so had a dexa scan just to see. This is coming in at 18% bf - a big difference. I wasn't  expecting the scales to be completely accurate.... but 10% off!!

I have tried changing the activity level on my garmin profile to be below 8, but this has made little difference. 

This is really frustrating as these scales aren't cheap and are now only really giving me a trustable body weight value. 

Anyone else had these issues? Anyone resolved these issues?



  • I noticed the ~10% drop also when adjusting the activity level to 8. Apparently it's some "athlete mode" that kicks in then, with different formulas. Since I am also skeptical of the too low % I readjusted to level 7 and body fat went up to ~17/18%. Not sure why they cannot make it gradual.

    Apart from this, I have had the scale since last fall and the measurements are very consistent. My pet peeve is that some 6 month graphs in Garmin Connect come out almost unreadable (for example, weight is plotted on a scale from zero to your weight, and so the curve appears to be too flat to interpret well. FOr some reason the graphs for a week and 4 weeks are done right.

    Related to this, I am curious about the activity level itself: is it defined by the sheer activity time, or do they mean "intensity minutes"?

  • I have been using these scales for two years and own many Garmin products..  I recommend that you return to retailer and purchase a competitors product.  It is okay at recording weight but the other metrics are useless.

  • see:      Body fat stuck at 7%     and prepare to wait another two years ... for 

  • Thanks for the feedback. Thinking of taking these back. Doesn't sound like a new issue and also confused about the calculation being tied to an 'activity level'.

  • I've seen several people post that the fat measurement stopped working properly when they changed their activity class to one of the top band (8,9,10). I'm on 6 and the scales work fine for me. If I weigh myself before and after a 30 mile bike ride I usually drop a kilo and some of that is fat. (obvs when I eat and drink again, some/all/more of that goes back on). Could you try changing your activity class to 6 or 7 and see if that makes a difference? 

  • Switching back from level 8 to 7 solved this for me.  Now my numbers are both (1) back within a few 1/10% of previous numbers and (2) within a few %/lbs of fat of the DEXA scan I just did yesterday (about a 10% error, so ~22% fat vs ~20%, ~45 lbs vs ~40 lbs)  I'm happy with that, as I know the type of measurement is not terribly accurate, which in my mind matches a ~10% error.

    That said, it does seem wild that there is such a huge jump.  On activity level 8 the scale claims I have nearly 7.5% less body fat, 2 lbs more bone, yet measures my muscle mass as nearly the same so that my "other" mass is nearly 15 lbs higher.  And while I am losing weight, so am not yet "trained," I do and have been working out 6 days a week for something like 8-12 hours per week for some months now.  It seems like there is a discontinuity in the algorithm(s)/formula(s) that should be addressed.

  •  It seems like there is a discontinuity in the algorithm(s)/formula(s) that should be addressed.

    Yes. Exactly that. I think that's what it is. It's like once some threshold is reached, it's all done a whole different way. Regardless of how much training I do, I'll be leaving my Garmin profile on level 6.

  • I have a Breurer index scales (BF 100) which measures using 4 sensors (feet and hands) and it has the same behaviour. On atlete mode (level 5 out of5) fat % drops from 16 to around 10%. Seems like a common behaviour for scales measuring fat.

  • My body fat goes up 6% when I change it from activity class 7 to activity class 8???

  • Having similar issue, and currently researching… I have 30% bf… I’m not fat… I compared my readings with friend who has previous model, hers shows 23%.  I’m 6 years older, same weight, same height, do same sport… don’t get it?