Using a Body Composition Scale

To do the following you need a body composition scale and a calculator.

If your scale tells you your body weight (as all scales do) and also tells you your body composition percentages the math is pretty simple to get to the lbs of body fat, water weight, etc.

To get the lbs of body fat take your body weight and multiply it times the percentage then divide by 100. For example, if your scale says you weigh 200 lbs with 30% body fat that’s:

200 x 30 / 100 = 60 lbs of fat

Some scales break out the water weight on it’s own and some include it by itself. If your percentages work out to more than 100% total then the scale is measuring body water independently of the other numbers.

My scale breaks weight down into:

  • Body Fat %
  • Body Water %
  • Muscle Mass %

So as an example if my scale shows:

  • Weight: 200 lbs
  • Body Fat: 32%
  • Body Water 37%
  • Muscle Mass 28%

That corresponds to:

  • Body Fat: 200 x 32 / 100 = 64 lbs
  • Body Water 37% = 200 x 37 / 100 = 74 lbs
  • Muscle Mass 28% = 200 x 28 / 100 = 56 lbs

Tracking the percentage is only so useful. What you really should care about is:

  1. Losing lbs of Body Fat
  2. Maintaining or gaining muscle mass

Water weight will follow since it tends to stabilize and increase with fat loss.

Bottom Line

Ignore your scale weight ups and downs. Instead do the math and track your lbs of body fat as well as your muscle mass numbers. They don’t tend to fluctuate as much as body weight.

P.S. Some Notes on Scale Accuracy

No scale is 100% accurate or even anywhere near it. But they are fairly repeatable and as such can be used for tracking purposes. For some useful notes on scales, here’s one article of many.


Author: Doug

I'm an Engineer who is also a science geek. I was pre-diabetic in 1996 and became a diabetic in 2003. I decided to figure out how to hack my diabetes and in 2016 found the ketogetic diet which reversed my diabetes.

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