Tanita Scales Query

TechnoFreek

Hi,

I have a question about the scales and its reading which I hope someone can clarify for me.
Wouldnt be familiar with the terminology or science so please go easy on me!

I jumped up on the tanita scales in the gym a few days ago and four weeks before that. On both occasions I weighed ten stone on the nose. Same time of day, clothing etc

However on the first reading I was 10.1% body fat. Four weeks later after some hard work I'm down at 8.9%.

In the same breath the trainer in the gym doing the reading said I had put on 3.5 pounds of muscle also.

Thinking about it later this doesn't make sense to me. General scale accuracies aside, at 10.1% bf that means just over 14 pounds is fat.

At 8.9% its 12.5.

That difference doesn't equal 3.5 of muscle gain?

Or am I misunderstanding how this is calculated?

Thanks.

Hanley

The scales are sh*te. They use an electrical current to measure BF% (fat/muscle/etc will all have varying degrees of "resistance" to the current).

But as you've found out - hydration status (pre/post workout) effects things too. The scales are less than useless.

Gillo

The simple answer is the trainer made a mistake in their calculations. That said those scales are awful at calculating body fat, the trainer should have been measuring using a calipers as they are a lot more accurate.

Dotcomdolly

Gillo wrote: »

The simple answer is the trainer made a mistake in their calculations. That said those scales are awful at calculating body fat, the trainer should have been measuring using a calipers as they are a lot more accurate.

I've an Omron one at home and it uses double impedance - there's a yoke you hold in your hands too - and it's just not believable. It says 35% , the pt did it with callipers and told me 17%! Which I don't believe either.
Barring getting a dexa scan ill have to be happy to go with what the mirror tells me, you can see progress in that pretty well

hollypink

I have a tanita scales and the body fat reading can vary by a few % from one day to the next. I was measured by a pt with calipers and was at 16% and the scales was saying anything from 20 to 24%. I only use it to weigh myself and just ignore the other readings.

Hanley

Also re: calipers - depending on the formula you use, the same readings can give a different %. So you really need to just worry about consistency and trend over time.

rubadub

Gillo wrote: »

The simple answer is the trainer made a mistake in their calculations.

Not necessarily.

TechnoFreek wrote: »

10.1% bf that means just over 14 pounds is fat.

At 8.9% its 12.5.

That difference doesn't equal 3.5 of muscle gain?

14.14-12.46=1.68lb difference in weight of fat. If he also lost water weight of 1.82lb then some might estimate this as 3.5lb of muscle gain.


You can see the tanita prinout here
http://www.scalesgalore.com/printout.htm

Impedance: Impedance reflects the body's inherent resistance to an electrical current. Muscle acts as a conductor of the electrical current, adipose tissue acts as a resistor.

Fat %: The percentage of total body weight that is fat.

Fat Mass: Total weight of fat mass in the body.

FFM: Fat Free Mass is comprised of muscle, bone, tissue, water, and all other fat free mass in the body.

TBW: Total Body Water is the amount of water retained in the body. TBW is said to comprise between 50%-70% of total body weight. Generally, men tend to have higher water weight than woman due to a greater amount of muscle.

You cannot simply presume that the difference in weight is due to muscle gain/loss. If the device was actually accurate then if I was 100kg and 10% BF then I have 10kg of fat. If I drank 2L/2kg of water and tested again straight away then it should show me as 102kg, and 9.804%BF. in both cases it shows I have 10kg of fat. Both FFM and TBW should have increased by 2kg in my second reading.

the groutch

because body fat changes so much in line with changes in body water levels, I add the two together and use the combined total to track progress.

Doug Cartel

Hanley wrote: »

Also re: calipers - depending on the formula you use, the same readings can give a different %.

I had body fat done once, and there was a 35% difference between the possible levels depending on which formula was used to calculate it. (I mean that the lower value was 65% of the higher value, btw. Not that one value was x% and the other was x+35.)