T Nation

Bodyfat % Discrepancies on Scales

I have a Tanita scale at home which indicates weight, bodyfat % and water %

Past few weeks I’ve been “testing” the bodyfat consistency of the scale and the results vary greatly. What I wonder is why this is and how do I find the “correct” number?

In my case, I’ve weighed and checked my BF% every morning after waking up and every night before going to bed for a week. My BF% is 2 to 4% lower when I check it at night as opposed to mornings. In my case this is 4lbs to 8 lbs of fat which is IMO physically impossible to lose over the course of a day or gain overnight.

Now I know, my main guidance to my progress is my mirror image, but it would be nice to know which my “true” BF% is. Also I keep wondering why this difference occurs.

Thanks in advance!

I’ve found those BF scales to be a waste of money. I’ve had a couple of the tanita’s and both of them varied greatly depending on how hyrdrated you are. A better option are those acu-measure body fat calipers. I don’t know how accurately the determine bodyfat, but they are great for tracking progress.

I used one recently which said I was 24% bodyfat.

The calipers said 16%.

You have to calibrate the scale properly to get accurate readings. For the Tanita models follow this procedure.

  1. Remove the batteries
  2. Get a #2 Phillips screwdriver
  3. Remove the bottom cover, 4 screws
  4. Remove the springs
  5. Put all of the parts into a ziplock bag
  6. Beat the bag with a Ball Peen Hammer
  7. Place the bag into the trash bin
  8. Spend another $70 on a good set of calipers

Scales are a poor indicator of bodyfat. I would go with Axel’s advice.

[quote]Axel44 wrote:
You have to calibrate the scale properly to get accurate readings. For the Tanita models follow this procedure.

  1. Remove the batteries
  2. Get a #2 Phillips screwdriver
  3. Remove the bottom cover, 4 screws
  4. Remove the springs
  5. Put all of the parts into a ziplock bag
  6. Beat the bag with a Ball Peen Hammer
  7. Place the bag into the trash bin
  8. Spend another $70 on a good set of calipers
    [/quote]

I have no idea how to use calipers or where to get them, any tips?

Are all these bio-electrical impedance techniques flawed or are there more accurate scales out there (like the Omron body composition monitor, etc)?

If you want an accurate measure you go to a real clinic that will do DEXA or underwater testing on you - for mere mortals, this isnt necessary.

Just measure yourself with your tanita scales and then do it at the same time of the day, before exercise, NOT just after a meal, and with the same drugs in your system (whether that is coffee, nicotine or PCP) - this will help to ensure the measurements are accurate to one another… Then you have a good way to measure progress…

Bioelectrical Impedence is supposed to be ±3% accurate, and when it is calibrated PERFECTLY i think that is likely!

Quoted from an unbaised site reviewing the different methods -

“Tends to consistently overestimate lean people and underestimate obese people”

JJ

I have just done 4 measurements -

The Jackson/Pollock 7 site - 9.5
The Jackson/Pollock 4 Site - 8.82
The Durnin/Womersley Caliper Method - 14.22
The Tape Measurement Method - 15.45

I know i aint 9% sadly, but i am not 15% either… so i tend to give the average of 12% - it isnt important what it REALLY is as long as i have the ‘ball park’ and as long as i see loss or gain.

FYI :wink:

the tanita’s aren’t all that bad as long as you measure yourself under the same exact conditions every single time. so for me it’s always on the same day and time, usually monday upon waking. first thing…take a piss, take a dump and of course don’t eat or drink anything. i’ve been able to consistently track my progress in this way. there are many factors that can throw the readings off. if you measure after you’ve worked out not too long before as opposed to having a day or 2 off can affect it. different times of the day, etc. so i think if you measure like i said…with always the same conditions, you should be able to obtain reasonably accurate readings.

are step on scales or hand helds accurate? “not really” my step on varies almost 8% from the hand held at the gym…but on the other side of that it does not lie,“sort of”

when im getting leaner the numbers go down. when my ass is getting fat the number goes up. so how accurate it is i don’t really care its a tool that works!

don’t take the numbers to heart and its still a useful tool

[quote]Axel44 wrote:
You have to calibrate the scale properly to get accurate readings. For the Tanita models follow this procedure.

  1. Remove the batteries
  2. Get a #2 Phillips screwdriver
  3. Remove the bottom cover, 4 screws
  4. Remove the springs
  5. Put all of the parts into a ziplock bag
  6. Beat the bag with a Ball Peen Hammer
  7. Place the bag into the trash bin
  8. Spend another $70 on a good set of calipers
    [/quote]

LOL. Indeed. For the 80th time, the scales are a piece of crap and extremely inaccurate. Get yourself a caliper reading, DEXA, or hydrostatic weighing.

I’ve found a great way to get shredded without diet or exercise. Take your Tanita scale and set the height to the max height and the age to the lowest value. recheck your body fat % - should be below 10%, unless you are already a fatass.

Also, taking a crap will drop your % down by 1 to 2 %

Your guesses ar more accurate