i just bought one of those things that you hold and it sends electrical impulses through your body to give you your body fat estimate. using the FIT index guide that came with the monitor, i am well into the Athlete mode. when i use the athlete mode, i come out to 8.5% body fat, but i put it in normal mode ( which is for people who dont exercise ) and it came out to 16.2%. what i would like to know is why the level of activity even makes a difference, if the thing is just supposed to be measuring the fat on your body. can anybody explain this to me?