What Your Smart Scale Isn’t Telling You
The science behind knowing your body fat percentage
After conducting research in a body composition lab on high-end bio-impedance devices, I realized how household body fat percent scales can be misleading. These “smart scales” can be extremely useful for fitness tracking. However, it’s important to understand the different types of devices to find the one that will work the best for your body type, and also what throws them off so they don’t tell you the wrong fat percent.
Bear with me, as a bit of background information helps to explain this (if you’d rather skip the science, scroll down past the next photo). Most household body fat percent scales use the same technology: bioelectrical impedance, or bio-impedance for short. That technical term means they send a small electrical current through your body to estimate your amount of fat mass and fat-free mass. If your scale has metal contact points and tells you a fat percent–it’s using bio-impedance.
The electrical current in bio-impedance devices can only see this fat-free mass, and are effectively blind to fat mass (fat is an insulator, like rubber, and doesn’t conduct electricity). So how do they tell us our body fat percent if they can’t see it?
