It is normal to see fluctuations in measurements. The human body is a living organism and is constantly in motion. Even when one hasn't moved or eaten, the body composition changes by the processes that are going on within the body.

Here you can read more about why your measurement results fluctuate or change:

Why do my measurement results fluctuate / change?

To get the best results from your TANITA it is important to measure under as similar circumstances as possible. Please check link below for more tips on how to get the best results:

How to get the best results from my TANITA?