Eli5 How does my scale know what my muscle mass, bone density, and water weight is?

Question

Eli5 How does my scale know what my muscle mass, bone density, and water weight is?

In: 1

Answer 1

It doesn’t.

What the manufacturer do is gather a large number of people and measure their muscle mass, bone density, etc. with conventional measurements. Then they use the scale – which measures electrical conductivity – and measure that for everybody.

Then they do a bunch of fancy math to come up with a model that works the other way – it takes a conductivity measurement – and predicts what the other values are.

It does a pretty poor job at it.

Answer 2

It doesn’t.

What the manufacturer do is gather a large number of people and measure their muscle mass, bone density, etc. with conventional measurements. Then they use the scale – which measures electrical conductivity – and measure that for everybody.

Then they do a bunch of fancy math to come up with a model that works the other way – it takes a conductivity measurement – and predicts what the other values are.

It does a pretty poor job at it.