Body fat on scales

me0231

So, I know that scales don't give an accurate body fat reading, but can they still be used for trends?

I've never really looked at the numbers, but I just looked at the graph over the last 8 or so months and since I started at the gym a three months ago I've seen a much sharper decline in body fat. For example, this last month I've got a new lifting program and I've been trying to get in my 10k steps every day. I'm still losing weight, but very very slowly, but body fat has been dropping quite steadily. Anyways, I'm really just wondering if I can put any stock in these numbers of if they're completely useless.

jemhh

They are not great for trends. A really good article on this: https://weightology.net/the-pitfalls-of-bodyfat-measurement-part-4-bioelectrical-impedance-bia/

BIA can be problematic because it's a prediction based off of a prediction, so the error gets compounded. When you look at group averages for BIA measurements, there tends to be bias, with BIA often underpredicting how much fat you have. As with other techniques, the individual error rates can get high, with some research showing error rates of around 8-9%. In fact, BIA doesn't do much better than BMI at predicting body fat in some cases. When it comes to measuring change over time, BIA can often underpredict the amount of fat loss, and the estimated change can be off by up to 8%.

For all of these reasons, I am not a fan of BIA for measuring body composition in individuals. If you are going to use BIA for tracking body composition over time, I recommend very long time intervals between measurements (at least 3 months, but 6 months is probably better), as the error rate for BIA can be larger than the changes in body fat in you see. Whatever numbers you do get using BIA, always remember they are very rough predictions....and I emphasize very rough.

me0231

Awesome, thank you so much. That's exactly the info I was looking for. I will continue to ignore them and keep on plugging away

leggup

Completely useless With lifting and weight loss.. take measurements instead! I use a $4 auto-tightening tape measure and measure about once a month/biweekly and find it inspiring.