Hey Kevin,
I also have a Tanita. I think the big caveat with the scales BF accuracy is that you must take a reading 3 to 4 hours after waking up, excersise, or eating solids. You can also try this website that has a good BF calculator, it can give you a good baseline - it is usually about 1% off from my Tanita scale.

http://www.healthstatus.com/calculate/bfb[/URL" target="_blank">

Hope this helps

iGot2Run

http://This message has been edited by iGot2Run (edited Jan-04-2007).

quote:<HR>Originally posted by tecdad:
Thanks for the link. I need to break out the tape measure this evening.

I think it is really hard to take a reading as you describe since I eat every 3-4 hours and exercise twice a day, so there doesn't seem to be a good time to take a measurement. I think the key will be taking consistent readings (same day/time)

<HR>

Same here, I can only get a good body fat reading a couple of times a week from the same reasons you mentioned. Sometimes if I don't snack after lunch I can get a good reading out of the scale when I get home.

Good luck.

Those scales are really just gadgets, but are quite inaccurate. A more accurate measure has electrodes on both the hands and feet and includes in the calculation age, weight, physical activity, height, etc. So I wouldn't be overly confident in the results given by the scale.

I've been coaching people to lose fat for years so I have a lot of data on the scales. What I've found is this:

1. They are incredibly accurate with weight ... I own a Tanita precisely because of how well and consistently it records my weight

2. They are notoriously inaccurate and inconsistent with body fat

The Tanita is great to show a trend in body fat, i.e. up or down. However, even if you pick the same time of day, etc, to weigh, there are so many factors that impact the reading that they are just nowhere near as accurate as a few other methods to consider.

The reading is made by passing an electrical current through your body. Fat offers a different type of resistance than other tissue and so by extrapolating the resistance encountered it attempts to guess at your body fat.

The problem is that water weight will throw off the reading (more "lean" or non-fat mass). Therefore, electrolyte balance can also impact this. If you go on a long run, don't rehydrate correctly, your body will begin to retain water and suddenly the scale is off. Stress, having a slowly digested meal, eating more meat, all of these can change what is in your body and impact the reading. Women have more fluctuations than men due to their menstrual cycles.

What I found is that most clients saw a normal trend until they reached what would be considered an extremely fit body fat percentage (teens for women, low teens or single digits for males). As they approached the lower body fat, the scale would just stall and stop showing any progress despite the weight going down.

This isn't due to settings, either, because we've experimented with the "athletic" settings, etc. What these really do is simply throw in a fudge factor and arbitrarily substract percentage points to get it closer to target.

I'd say the scale is great for a general trend (i.e. if you take the average over a week and that is going down, you are probably reducing body fat) and fantastic for actual weight.

If you want reliable body fat, though, there are other easier methods.

By far the most accurate is body fat caliper. The issue here is that people want to throw it into equations and say, "I'm 9.4% body fat" instead of using it as a relative tool. For example, I personally stay really lean on my arms, upper chest, etc. I carry my fat mainly on my abs and thighs.

Skin is only a fraction of an inch thick. Heard the expression, "Can't pinch an inch?" This refers to the fact that even if you have "loose skin" from losing weight, if you pinch your skin, it should only be fractions of an inch thick if you have not fat underneath it. When you pinch any part and are able to pull a pinch that is thicker, the extra thickness is from subcutaneous (beneath the skin) fat. So this becomes a measure of body fat. Without even computing a percentage, you can simply record the thickness of various pinches in millimenters.

As an example, instead of obsessing over some body fat number, I know that I can see my abs and am lean when my abdominal pinches are 8mm and my thigh pinches are 6mm. So, if I pinch now and get 24mm, I know I need to lose. Instead of tracking body fat, I'll track mm of that pinch from week to week. If it's going down, I'm losing fat.

Another VERY easy measure is the biceps-to-waist ratio. Take the circumference of your waist just below the belly button. Then, take the circumference of your UNFLEXED upper arm (biceps) at the widest point. Waist/Arm = ratio.

So if I have a 36" waist and 18" biceps then my ratio is 2.0. If the ratio goes UP, I'm gaining fat and possibly losing muscle. If it goes DOWN, I'm losing fat and gaining muscle.

I.e. if I drop my waist to 32" and maintain the 18" biceps, then my ratio becomes 1.8.

One thing I suggest is not to worry too much about standards and averages. For example, I'm supposed to be obese at my BMI despite a lower body fat. I was a shredded 6% body fat at 178 pounds yet all of the charts said my "normal weight" was 150 ... a weight where I'd look withered away and sick.

I'd use things like pinches, scales, etc, as a way to gauge progress but success is based on how you look and feel.

Jeremy

That's great info Jeremy. Unfortunately, there in not likely any place I can pinch skin and find less than 6mm - well maybe one - and we just don't pinch there. I had hoped the BF measurement would be consistent from day to day. If it reads 20.0%, I don't really care if that represents 18.0% or 22.0% so long as it reads 20.0 the next day. I would like to see any change as soon as possible but I don't want to see false changes.

------------------
gotta run...

I have a tanita bf/body water scale, and mine's not super consistent, but falls around 20-22. I think you could do as Jeremy suggested, and take maybe an average over a week, measuring at the same time of day, and that would be a pretty consistent number to use.

Jeremy or willbevan, do you have a particular set of calipers that you like? Or, is there a good place that I could go to be tested on the cheap? I think I'm in the best shape I've been in since I was um... ten, and I'd like to know what my bodyfat compares to what I was in highschool (which was always 28% or above). I guess the thing is that I'd like a reliable measure of my bodyfat to compare, but I don't know if I'm worried about it being correct to the 10th of a percent all the time.