I have a scale that pops out the BMi and body fat %. I do not think it is any different than a regular scale except that it is doing a quick calculation (I mean, I do not think it is measuring anything but pounds). Anyway, as I am losing weight, the BMI is going down, but the fat % seems to be staying the same and/or going up from day to day. Can someone clue me in on exactly what this means?

Are you sure it's just calculating? Most scales of that type measure body fat percentage by bioelectrical impedence (ie, shooting a small electrical charge up through your feet to measure how quickly the signal returns, which is then used to calculate body fat percentage).

If your weight was going down and your scale was just calculating, the body fat % reading would go down. Since it isn't, it indicates this is probably a bioelectrical impedence scale.

If you are losing weight, but body fat percentage is staying the same or going up, you may be losing muscle. This link has a very good example with the graphs of how this would work. Exercise makes a big difference in which way that trend will go as you lose weight. Keep in mind, though, that these scales show trends over time, and will fluctuate regularly, so you won't see a downward trend every day (just like a scale).

Thank you so much. I was a bit perplexed by this. I had no idea my scale could actually measure that! Cool. I have been spending a lot of time on the treadmill (for me), but maybe I need to add some weight resistance of some kind.