Bathroom Scale

[Possegal]

Mine is a Tanita. And it actually makes sense that your body's hydration state will affect the reading.

See two posts here on this board where others talk about the same thing.

http://forums.teamestrogen.com/showthread.php?t=22661
http://forums.teamestrogen.com/showthread.php?t=25177

What mine does is say ERROR and the papers with the scale say that it will read error if your body fat is over some high number, though honestly it was a while ago and I can't find the brochure to know what the number was. I just remember reading it and freaking out. Then I searched, and then the science of it also made sense. In the afternoon, I read something in the 30s (still horrid, but not as bad as I thought based on the morning). It is probably something far more problematic for big fat people like me!

But scientifically, time of day will affect anyone doing these readings because your hydration levels vary and that is how it measures percent body fat.

Here is what Tatina says about when to do the reading:

As your total body water level changes naturally throughout the day, this may affect your body fat percentage readings. First thing in the morning you will be dehydrated and the fluid in your body will be stored in the central trunk area. As the day progresses, this fluid becomes more evenly distributed and, of course, eating and drinking will also affect your total body water level. So even though your actual body fat mass will not change during the day, your body fat percentage will, as your total body water changes. Your body fat reading could vary by as much as 3-4% in a 24-hour period.

Consistency is the key to using your Body Fat Monitor. The best time is in the early evening, before your meal, when hydration levels are more stable. This increases the accuracy of the readings. If you are unable to use your Body Fat Monitor as this time, pick a time that's convenient for you and stick to it. Take your readings at the same time and under the same conditions each day.

Of course with me, it could be a combination of me being a lot of fat, me having more than the average level of hydration fluctuation in the day, and my scale not being all that great despite others liking the brand.