How can a scale tell your body fat?

A scale that claims to measure body fat percentage usually relies on a technology called bioelectrical impedance analysis (BIA). Here's the detailed explanation of how it works:

1.Sending an electrical signal: When you stand on the scale, it sends a weak, painless electrical current through your body. This current is so mild that you won't even notice it. The electrodes on the scale are responsible for transmitting and receiving this electrical signal.

2.Differential conductivity: The electrical current travels through different types of tissues in your body at different speeds. Fat tissue has a high resistance to the flow of electricity because it contains less water and fewer electrolytes compared to lean tissues like muscles, organs, and blood. Lean tissues, on the other hand, are better conductors of electricity due to their higher water and electrolyte content.

3.Measuring impedance: As the electrical current passes through your body, the scale measures the resistance or impedance that the current encounters. Higher impedance indicates a greater amount of fat tissue in the path of the current, as fat resists the flow of electricity more than lean tissue does.

4.Calculating body fat percentage: Based on the measured impedance value, the scale uses a mathematical formula that takes into account other factors such as your height, weight, age, and gender. These additional factors are important because they affect the overall composition and distribution of tissues in your body. Different formulas may be used by different scale manufacturers, but they all aim to estimate the proportion of fat in your body relative to lean mass.