Just got the index S2 today, what a joke product. Quickly confirmed that if you set your activity level to 5 , it only uses weight (and the stored age / sex) input to provide BF%:
The algorithm used seems to be:
Body fat % (Adults) = (1.20 × BMI) + (0.23 × Age) - (10.8 × sex) − 5.4
where sex is 1 for males and 0 for females.
Anyone else can confirm this?
Very disappointing and I would guess bordering to illegal to market this scale as actually using impendance measures? Maybe the software is broken and fails to get impendance data and just falls back to use weight? And Garmin is not fixing it? Mind boggling ..