Info on Bioelectrical Impedance Analysis (Body Fat Meter)

I was wondering if anyone has any experience or knowledge about Bioelectrical Impedance Analysis? I purchased a scale a while back that was supposed to give me my weight, hydration level and body fat percentage.

My healthy teenage daughter gets on it - she weighs 140, 69% hydrated, 18% body fat.
My slightly stout preteen son gets on it - he weighs 180, 67% hydrated, 20% body fat.
A Dangerously Unqualified Domer gets on it - he weighs 325, 37% hydrated, 57% body fat.

Um... This can't be right can it? I mean, I accept the weight but isn't the body fat a little overstated and the hydration way off in left field? If I were actually only 37% hydrated wouldn't I be quite sick?

I have been working on getting my hydration number up but have not brought it above 39% and the more water I drink the worse it gets.

Is this scale correct?
And if it isn't, will it get more correct when I lose weight?
What would be a good target then: losing weight, dropping body fat or raising hydration?

I had thought that dropping body fat would be a good target independant of weight loss as I realize lean muscle weighs quite a bit more than fat. In fact one of our children has lost several inches and has clothes fitting quite a bit looser but is upset because she weighs the same after weeks of exercise. So I'm not as hung up on weight as I am on losing body fat and getting in good shape. Is this device a reasonable measurement of this or am I the proud owner of an expensive but otherwise singularly functional scale?

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Originally posted by Dangerously Unqualified

I was wondering if anyone has any experience or knowledge about Bioelectrical Impedance Analysis? I purchased a scale a while back that was supposed to give me my weight, hydration level and body fat percentage.
...
Is this device a reasonable measurement of this or am I the proud owner of an expensive but otherwise singularly functional scale?

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Sad to say, but I would trust your device as an accurate scale and not much more. My fat content has stayed constant as I dropped 60 odd pounds, lost 5-6 inches off my belt, got fit enough to run a 10k, and a simple visual inspection gives lie to that figure. My H[sub:10d6cihm]2[/sub:10d6cihm]O % fluctuates wildly. So I just trust the weight. I'd dearly love to find somewhere with a BodyPod (the gold standard for fat content measuring) to check my real numbers. That said, I saw a show with a real Doctor (gyno) investigating the diet industry, and she got into a BodyPod and was measured at 25% fat. She certainly didn't look like it. She gave a group of people "diet pills" that were to be taken along with a sensible diet and moderate exercise, and 80% of the group lost weight over a 12 week period. [spoiler:10d6cihm]The pills were placebos. :smack[/spoiler:10d6cihm]

Si

It seems that one of lifemeasurement's Body Pod products is actually called The Gold Standard. This looks awesome as far as measuring goes. I also noticed that their website has a form to submit and they will let you know where their products are in case someone wants to check one out.

I know in my heart and in my head that the only path to weight loss is hard work, excercise, maintaining a healthy diet and making good decisions. I was just kind of hoping to have an accurate and personal tool so that when I'm busting my ass at the gym and my pants size is going down but not my weight I can see the part of the equation that the scales don't tell.

Maybe I will be better off shunning all metrics and just, quite literally, work my ass off.

My Tanita scale is an accurate scale, but the impedance thing has never worked. I got it a few years back when I was starting to lose weight and it said that I was 26.something% body fat. I've lost over 10 kg since then, but it has never read lower than 22% that I can recall.

I have been at roughly the same weight for a few months, though I've leaned out a bit and put on a bit more muscle. The body fat calipers I bought on a recent trip back to the US say that I'm somewhere around 9%±2%. That is probably pretty close to being right considering I can see the outlines of stomach muscles with a thin layer of fat over them. I'll bet the scale still says I'm somewhere around 20%.

Don't really worry about it. You are unquestionably overweight. Find an exercise program. Keep doing it. If you start to get bored, find something else that you'll like. Don't stop exercising. That alone will make you more healthy even if by some miracle of thermodynamics you don't start losing fat.

Make some adjustments to your diet. Do not crash diet. Any changes need to be sustainable. That means that you need to consider those changes to be permanent, which is why you start small. Honestly assess what you eat normally and think about what small changes you could make. Cutting 500 daily calories is a relatively painless reduction, but will have effects over the long term. If your intake is really high, you could probably cut a bit more after an adjustment period of a couple of weeks.

A lot of people like Spark People. I personally don't use it — I eat more or less like the Zone if left to my own devices and just needed to spot check myself for portion control — but there are quite a few who have found it useful.

I do CrossFit but could not recommend it for a total newbie in your kind of shape. You can take the basic principles and adjust them for your circumstances, but doing so would require more advice than I can give in a message board post. If you're interested, find a CrossFit affiliate and work with one of the trainers. They should be capable of scaling workouts for everyone from kids to seniors, and the reform-minded overweight to advanced athletes. Self-scaling is possible, it's how I did things, but requires at least some background in fitness, or a lot of research and cautious trial and error.

One short bit of workout advice I can give is to do both muscle training and aerobic work. They complement each other. Doing either/or is not as effective as doing both. Longer is not necessarily better when it comes to aerobic work. Starting out, find something you can do (walking, swimming, cycling, rowing, whatever) at a moderate to tiring pace for about 20–30 minutes. You should find it challenging but not exhausting. If you can do it for more than 30 minutes, you're probably not going hard enough. If you're going face-down at 15 minutes, you're overdoing it — at this point anyway.

Measure your progress by performance, not just reductions in body weight.
e.g.: "Last time I did this weight, this session I could lift this much."
"Last time in 20 minutes I made this distance, this time I got 200 m farther."

Body composition measurements are only one part of the story. The things that have real effects on your life are how strong you are, how fast you are, how long you can go. Ultimately those metrics are both easier to quantify and provide a continuing measure of progress. The barbell doesn't lie, neither does the stopwatch, and both of those are more accurate measurements of fitness than the scale.

Remember that it will take time — years probably — to get into the kind of shape you'd like to be. It took me close to a year to both lose the relatively small amount of weight I had, and get to where I was pretty happy with how fit I was. I've been working out regularly for close to two years now. It will take you longer because you have more to lose. Think of it as a lifestyle change rather than a fitness/diet program, because if you want to lose weight and keep it off, that's the only way to do it.