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Bioimpedance Scale Accuracy After Eating and Urinating

Daniel Brady | January 4, 2013 in Equipment
Beurer BG51 XXL Diagnostic Scale

Bioimpedance Scales sometimes get a bad rap from people who don’t trust their accuracy. So I tested an average $100 scale, the Beurer BG51 XXL Diagnostic Scale, before eating breakfast, after breakfast and then after urinating. Read on to see how accurate it was.

Initial Result

My initial result was taken before breakfast and before urinating, it read 11.4% fat and 64.7kg weight.
Bioimpedance Results Before Breakfast

After Breakfast

I had a fairly large breakfast consisting of 500ml whole milk, a cup of oats, half a cup of cornflakes and 1 scoop of gainer powder. My result after eatign this was 11.7% fat and 65.3kg weight. The scale treated my new stomach contents as equal parts muscle, fat, bone and water. In turn this increased the body fat reading.
Bioimpedance Results After Breakfast

After Urinating

After urinating my results returned identically to the initial result, so I must have urinated about 600ml, the equivalent of what I ate for breakfast. So the machine treats stomach contents and bladder contents the same.
Bioimpedance Results After Urinating


This machine would be skewed by things such as sweating, drinking, eating and urinating. So if you want reliable comparison readings, you have to test under the same circumstances each test, preferably after urinating but before breakfast, then your side by side readings will be a reasonably accurate representation of your improvement or regression. If biasing factors are minimized, this test is useful to do every week or so. Write down or chart the results to see the trend over time.

Daniel has a strong interest in evidence supported fitness training, preparation and supplementation. His goal is to provide clear information that simply works. He's currently 16 kg of muscle above his starting weight (7kg in the past 12 months), and targeting a continued growth rate of 5kg+ per year.
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