Originally Posted by
MoAlpha
Yes. Each of these components has a known conductivity and I'm pretty sure the body is modeled as a set of parallel impedances. I'd be willing to bet that glycogen content doesn't affect the conductivity of muscle much.
Incidentally, you don't necessarily pee out the water bound in glycogen, nor the water formed in the metabolism of carbohydrate to water and CO2. It goes into the plasma just like any water you drink and if you're working out, it leaves the body as sweat and respiratory water as much as urine.
https://tanita.eu/body-composition-scales/
Water content changes muscle conductivity. My muscle percent between when I get up and later in the day goes up 1 or 2 percent. Similarly after exercise and my thighs are still pumped, it also goes up. However if I don't recover the lost glycogen, the next mourning my muscle percent number will have gone down 1 or 2 percent from the previous morning as well as my weight dropping 1 - 1.5 lbs.. I doubt that's from dehydration since I pee a few times in the night no matter what. OTOH if I do recover the glycogen, neither my morning weight nor muscle percent will have changed. It helps to have paid attention to one of these scales for many years. Whether that's glycogen being measured or simply the water content of the glycogen really doesn't matter. It does get measured.