Yo team — I just devoured Victoria Song's piece over at The Verge and it honestly changed how I look at my fitness tracker. She measured her body composition across five different devices, and the results are wild because they tell you more about what BIA technology actually is than any marketing blurb ever could! Her FitBit said 37% fat; an Omron scale gave 28-31%; Withaings fluctuated between 29% and a staggering 40% on its own app; Garmin read out at 35%, while the Dexa machine—the actual gold standard reference — landed her somewhere in that ballpark. When one person gets five different answers from five devices all marketing themselves as accurate, it's hard not to ask what we should actually trust with these numbers!
The real story is under BIA (bioelectrical impedance analysis), which doesn't measure fat or muscle directly but instead sends a tiny electrical current through your body. The problem? Fat and water conduct electricity differently, so any fluctuation in hydration can swing the result by double digits — that 29% to 40% jump on Withings is almost certainly a hydration shift, not a real change in composition! That's why she notes Dexa gets close (within about two percentage points) while BIA devices all over the board diverge wildly. Her big takeaway is what I want you to remember: ignore any single body fat reading as gospel — it's too variable to be meaningful on its own, but your six-month trend across these trackers can actually tell you something valuable. The number itself matters less than where it goes over time because that smooths out the day-to-day noise created by how much water you drank or how hard you just worked out!
Source: https://www.theverge.com/column/957703/optimizer-withings-dexa-body-composition-health-fitness
Also see: https://shop.wowser.io/wiki/how-it-works
The real story is under BIA (bioelectrical impedance analysis), which doesn't measure fat or muscle directly but instead sends a tiny electrical current through your body. The problem? Fat and water conduct electricity differently, so any fluctuation in hydration can swing the result by double digits — that 29% to 40% jump on Withings is almost certainly a hydration shift, not a real change in composition! That's why she notes Dexa gets close (within about two percentage points) while BIA devices all over the board diverge wildly. Her big takeaway is what I want you to remember: ignore any single body fat reading as gospel — it's too variable to be meaningful on its own, but your six-month trend across these trackers can actually tell you something valuable. The number itself matters less than where it goes over time because that smooths out the day-to-day noise created by how much water you drank or how hard you just worked out!
Source: https://www.theverge.com/column/957703/optimizer-withings-dexa-body-composition-health-fitness
Also see: https://shop.wowser.io/wiki/how-it-works