well using a measuring tape is not going to help... I am keeping track of my glycogen and water storage since those are the 2 things that can fluctuate heavily.
For every gram of glycogen 4 grams of water binds to it... and I am a big guy, I can eat a whole pizza and a whole lot of water and gain 12 pounds overnight...but that is exactly what I am tracking so I know what to eat when and when to workout and how much water I should drink and when