It can t tell you how much of your total body weight is lean tissue and how much is fat. There are several other measuring techniques that can accomplish this, although they vary in convenience, accuracy, and cost. The best measurement tool of all turns out to be your very own eyes. These are the true measurements of success. If you are exercising and eating right, don t be discouraged by a small gain on the scale.
Fluctuations are perfectly normal.
Expect them to happen and take them in stride. It s a matter of mind over scale.