Thank you. I needed that.
Yes, I’m urinating. I have a requirement to drink about a half gallon of water a day, so I’m peeing frequently. With the vitamin supplements I take, it’s a very entertaining shade of yellow, too…
In addition to urination, could there be other exit routes for mass during a session of intense defecation? Does the stress increase carbon dioxide output (described in this thread as the major end result of fat metabolizing)? Would gasses released anally during the defecation amount to much? A short but dramatic increase in rapidly-evaporating perspiration? If a three-pound loss in feces alone seems unlikely (and assuming the scale is accurate - I’ve noticed some randomness on weighings only minutes apart without an intervening mass-loss), where would the rest go, and how?
As a minor side note, an episode of CSI showed an investigation of the death a model who (they learned) had become insanely obsessed with her weight, to the point of self-mutilation. When investigating her home, the characters found her various tools for accurately measuring her fecal and urinary output but it occured to me that living in Las Vegas, her most likely route for lost mass was simple perspiration.