Last year I bought two Tanita Body Fat Monitor scales, one for me and one for my family. They were on sale for $40 (original sale price of $120). http://www.amazon.com/Tanita-BC533-Innerscan-Composition-Monitor/dp/B000... Right now the price is $88, but some others are around $50.

Anyway, as with any scale the weight measurement is the most accurate and most used feature. It also calculates body fat % each time you step on, but I've found that reading to be highly variable. For about 2-3 months it read 5.0% for me which I suspect is the minimum it ever displays because it never budged lower. This week it recently shot up to 7.X and a few marks in between. It calculates BF% based on the speed an electric current passes through you, so hydration and other factors can cause a big change. But I figured that by recording the reading each day I'd get good average results. As far as using it for training, I don't think the scales are accurate enough to tell you when to change your nutrition or when you are dehydrated. Instead, I will use it to keep track of my race weight and body fat from different seasons and see how it impacts my performance.

The most reliable way to see if you are well hydrated is to look at your pee. If it is clear or light yellow you are fine, anything darker indicates dehydration. Similarly, nutrition intake is best determined based on advice from books and then experimenting yourself. If you feel low on energy, unrecovered or end up bonking in a serious workout, a nutrition change may be required. As for the other fancy readings (water %, lean mass, visceral fat, caloric age, bone mass, physique rating etc) I rarely ever use them. They are fun numbers to compare with friends but I have never trusted the reliability.

Overall, I love my tanita body fat scale but it certainly isnt necessary for monitoring your nutrition. I would get one again at $40 but I think $90 is too much for what it provides versus an ordinary spring-scale.

cool - pea pee:)

/k

I had some prescription vitamins at one point - the doc warned me I'd pee bright yellow/green and he was NOT KIDDING. My current B-heavy multivitamin does it too.

Anyways, I have a Tanita scale with the body fat and whatnot. I have very mixed opinions on it.
I also found it to be highly variable. For a while when I was experimenting with it I weighed myself every few hours and might register anywhere from 8%-12% fat within a 48 hour span. Averaging results is useful - over the course of about 2 months I lost almost 10lbs and reduced BF from 12% to 10% - but those observations were only possible by plotting it in excel! With the day to day variability, that trend would have been totally lost in the noise. Sure I remember noticing a lot more readings that were below my target points, but if I went back later that same day and was back up 2lbs and 2% fat, it was really hard to tell.

I have a standard Tanita scale but they also offer an "Ironman" series that I sort of wish I would have gotten just because the Ironman scales calculate a Basal Metabolic Rate (calories burned daily with no activity) whereas my scale calculates a "Daily Caloric Intake" which is a BMR multiplied by some unknown "Activity Factor" that you set with a scale of 1-4 or something ridiculous describing how "active" you are. Not that I would trust too much in BMR or DCI calculated off the scale because your individual rate varies, but my scale tells me I can eat over 3500calories a day to maintain my weight, which is only accurate on days with longer than average workouts. I think I have it set at 2 out of 4 for activity. If I were using the Ironman series, it would probably report more like 1700 for BMR, which I calculate in my spreadsheet, but it'd be nice to see it right on the scale. It'd be a bit easier to budget for the day because you know that if you don't do anything, you should stay closer to your BMR, and if you have a hard day, you should add the estimated calories burned for your workout.

If you're not a numbers geek like me, any digital scale that gives you an exact weight reading will do. If you're up for it, though, tracking weight and BF% plus daily intake (weighing your food and such) and daily workout estimates can be a really interesting experiment and you'll definitely learn a good bit about how your body works, even if the scale isn't a precision scientific instrument.

Oh, and as far as the H2O readings on the scale, I give that very little credibility. I never saw it lower than 60.0% or higher than 63.5% and got a lot of noise in between. Within that narrow of a range, noise overpowers any real results by far. I suppose if I had noted in my logs what it was immediately before and after a workout I could try to extract some meaning from it, but that would have required some pretty intense logging.

-Grant-

If you eat enough asparagus, your pee not only smells, it turns a strange yellow-green color as well.